The main reason I recommend making this change is improved security. On shared hosting servers, without extra steps being taken every Web site uses the same temporary directory for its sessions. This means that dozens upon dozens of applications are all reading and writing in the same place.
Queries could be run indicating the number of active sessions and session data can even be backed up. A third reason to store session data in a database is if you have a site running on multiple servers.
When this is the case, the same user may be fed pages from different servers over the course of the same session. The session data stored in a file on one server would be unavailable to the pages on other servers. Tip Another fix for the security concern on a shared host is to change the session directory for your site. Creating the session table To store session data in a database, you must first create a special database table for that express purpose. This table can be part of an already existing database like the rest of your application or in its own database.
At a bare minimum, the table needs three columns Table 3. Table 3. Session Table Columns The session table can have more than those three columns, but it must have those three. To create the sessions table 1. Access your MySQL database using the mysql client. You can also use phpMyAdmin or whatever other interface you prefer. Select the test database. The table contains the basic three fields. The id is the primary key. It will always contain a string 32 characters long and can never be NULL.
Defining the session functions After creating the database table, storing session data in a database is a two-part process from a PHP perspective : 1. Define the functions for interacting with the database. Tell PHP to use these functions. This function should be called with six arguments, each a function name Table 3.
That function must always return a string, even if that means an empty string. Before getting into the script, it helps to understand when the different functions will be called. The logical flow of using sessions and the various session-handling functions. To create new session handlers 1. I initialize it here and then make it global in each function. Script 3. This script defines all the functionality required to store session data in a database.
It can be included by any page that wants that feature. The intent of this function is merely to establish a database connection.
It will close the database connection, returning the success of that operation. The function needs to retrieve the data for that session ID from the database and return it.
If a record exists whose primary key is the same as that given a value in this query i. Otherwise, a new record will be made.
Session data is stored in the database or in a file as a serialized array. This serialized value says that indexed at blah is a string six characters long with a value of umlaut. Indexed at this is a decimal with a value of Indexed at that is a string four characters long with a value of blue.
As an example of changing the returned value, you could have this function return the number of affected rows: 1 would effectively be true and 0 would be false. So garbage collection is triggered by any session but attempts to clean up every session. As for the garbage collection function, it will receive a time, in seconds, as to what is considered to be old.
Second, you must use these two lines in this order. Tip If session. Tip As of PHP 5. For example, you can use the Session-Handler class. This will mean more after the chapters on object-oriented programming. Almost everything else you would do with sessions is unchanged, from storing data in them to accessing stored data to destroying a session.
As is often the case, there is one little tricky issue All of the session activity requires the database and, therefore, the database connection. The connection is opened when the session is started and closed when the session is closed.
As you may already know, PHP does you the favor of automatically closing any database connections when a script stops running. For this next script, this means that after the script runs, the database connection is automatically closed, and then the session functions attempt to write the data to the database and close the connection. To use the new session handlers 1. This conditional is being used to replicate sessions on multiple pages. The first time the page is loaded, new data will be stored in the session.
If the user clicks that link,? Unlike that line, this one will apply the first time the page is loaded. It will also be used to reveal the effect of destroying the session. Save the file as sessions. The result the first time the page is loaded.
Reloading the page allows it to access the already-stored session data. Working with U. Zip Codes A common need on many Web sites is to be able to perform distance calculations between addresses. Although you can always go the full MapQuest or Google Maps route, simple distance estimates can be managed using just zip codes in the United States, that is.
For every zip code, there is an associated longitude and latitude technically, zip codes represent multiple longitudes and latitudes, but one pair can be considered centrally located. Take two of these points on the earth, throw in some complicated math, and you have an approximate distance.
Creating the zip code table This whole example is predicated on having a database with the latitude and longitude points for every zip code in the United States. The second option is free free! Census Bureau for its own purposes. This database ignores around 10, zip codes that are used internally by the U. Post Office or by specific corporations. It also groups some zip codes together and uses characters to represent others.
But for some uses, this information will do just fine. To create the zip code database 1. Find your data source. Which source of the types and specific ones outlined you use depends on your situation.
How important is accuracy? How much are you willing to spend? The only real criticism of this source is that the latitude and longitude are only precise to a bit more than a half mile, but the data is current, and free! Some sources may already provide the necessary SQL commands to create the table and even insert the data, in which case you could skip Steps 3 and 4. If not, you should create a table whose structure matches the data to be inserted.
The zip code column, which is the primary key, should be an unsigned, zero-filled integer five digits in length. The latitude and longitude columns should be some type of fixed-point number. As an aside, the word decommissioned is misspelled that way in the data file, hence the matching misspelling in the SQL command. It may take you a while to get this step working properly you may also have more luck using phpMyAdmin for this.
For this step to work, the number of columns in the table must match the number of values on each row in the text file.
See the MySQL manual for more information on this syntax. The name of the text file should match the absolute path to the file on your computer. Using the downloaded data that includes a header line , I also had to remove that line from the CSV file prior to this point. Add indexes and update the data, if necessary.
Cleaning up the table to make the data more usable. In terms of updating the data, you could, for example, turn empty latitude and longitude values into formal NULL values.
Some of the warnings from the recent query the data import. Therefore, a stores table is necessary. This table can contain whatever information you want. Likely, it would be something like Table 3.
To create the stores table 1. Access the zips database using the mysql client or another interface. The table models the data suggested in Table 3. The result of the distance calculation, using the latitudes and longitudes from. Optimizing Joins The MySQL database application does a lot of work to improve efficiency, often unbeknownst to the common user.
This may involve changing the definition of a column or secretly altering how a query is run. But sometimes MySQL needs a little help. Joins are expensive queries in terms of database resources because they require conditional matches to be made across two or more tables.
To encourage MySQL to perform these joins faster, you should do two things. First, an index should exist on both columns. Second, both columns should be defined in exactly the same way. To calculate distances in MySQl 1. This PHP script will return the three closest stores, using a zip code calculation, to a given zip code. That information will be necessary for calculating distances between the given zip code and each store. This may not be necessary for all data sets. The phone number is also returned.
The result of the main, rather unwieldy, query. The big, complex calculation is also selected. Only three stores are going to be returned, and they are ordered by the distance value, from smallest to largest. The result should an invalid zip code like here be used.
Save the file as distance. The closest stores to the zip code. Change the zip code and test again. Creating Stored Functions Stored functions are half of a larger concept called stored routines the other half are stored procedures. Present in many database applications but new to MySQL as of version 5, stored routines allow you to save a set sequence of code in the MySQL server, and then call that sequence as needed. The topic of stored routines can be expansive, but I want to give you a little taste here.
Declaring Local Variables Stored routines are like small programs, and they can even have their own variables. END code block. As with most things you name in MySQL, you should stick to alphanumeric characters and the underscore. The arguments section is used to pass values to the routine. This can cause a problem: when you go to add this stored function using the mysql client or phpMyAdmin, the interface will think that the semicolon indicates the end of a command to be executed immediately.
I normally use two dollar signs together. Functions return scalar single values, like a number or a string. You cannot return a list of values from a stored function, but because stored functions return scalar values, they can be used in queries like any of the existing MySQL functions.
To create a stored function 1. You can also use phpMyAdmin or any other interface you prefer. Select the database where you want to define the function: USE zips; 3.
Doing so will simplify the calculation to a degree pardon the pun. This is the same test query run earlier in the chapter, except now it calls the stored function. If you want, modify distance.
This also means that you cannot have a stored routine select a database. Displaying Results Horizontally Another of the common questions I see involves displaying query results horizontally.
To achieve a horizontal layout, you have to create an HTML table. The trick, truly, is knowing when to create new rows in that table. A traditional vertical display of some records. The same data as in , laid out in table form. To achieve this effect using PHP, you need a counter that tracks how many records have been placed on a row i. When zero records have been placed, the new row should be started. When the maximum number of records has been placed, the old row should be concluded. To display results horizontally 1.
All of the cities and zip codes for a given state are retrieved by this PHP script. Just changing this one value will allow the script to output the results in fewer or more columns. Then the counter needs to be reset so that the next time the loop is entered, a new row will be started. Unless the number of items displayed is easily divisible by the number to be displayed per row i. A little-known trick with the for loop is that each of the three parts is optional. The last row had only four items in it, so one blank table cell had to be created.
Save the file as display. With two quick changes, the script now displays all the cities for another state here, Hawaii , four per row. See pages 91 and How do you create them?
Why is that sometimes necessary? And while it is possible to have a good career without learning and using OOP, you should familiarize yourself with the concept.
At the very least, being able to use both OOP and procedural programming allows you to better choose the right approach for each individual project. In this chapter, I will use somewhat mundane examples, but in subsequent chapters, practical, real-world code will be used. Through multiple examples and plenty of explanation, I hope in this book to fully demonstrate not just how you do object-oriented programming in PHP but also when and why.
OOP Theory The first thing that you must understand about OOP is that it presents not just new syntax but a new way of thinking about a problem. To explain All programming comes down to taking actions with data: a user enters data in an HTML form; the PHP code validates it, emails it, and stores it in a database; and so forth. These are simply verbs actions and nouns data.
With procedural programming, the focus is on the verbs: do this, then this, then this. In OOP, the focus is on the nouns: with what types of things will the application work?
The two most important terms for OOP are class and object. A class is a generalized definition of a thing. Think of classes as blueprints. An object is a specific implementation of that thing.
Think of objects as the house built using the blueprint as a guide. To program using OOP, you design your classes and then implement them as objects in your programs when needed. One of the tenets of OOP is modularity: breaking applications into specific subparts.
Web sites do many, many things: interact with databases, handle forms, send emails, generate HTML, etc. Each of these things can be a module, which is to say a class.
Related to modularity is abstraction: classes should be defined broadly. As an example, instead of designing a class for interacting with a MySQL database, you should make one that interacts with a nonspecific database. From there, using inheritance and overriding, you would define a more particular class for MySQL. This class would look and act like the general database class, but some of its functionality would be customized. Another principle of OOP is encapsulation: separating out and hiding how something is accomplished.
Coupled with encapsulation is access control or visibility, which dictates how available components of the class are. Those are the main concepts behind OOP. First of all, know that OOP is not a better way to program, just a different way. In some cases, it may be better and in some cases worse. As for the technical negatives of OOP, use of objects can be less efficient than a procedural approach.
The performance difference between using an object or not may be imperceptible in some cases, but you should be aware of this potential side effect. A second issue that arises is what I have already pointed out: misuse and overuse of objects. Whereas bad procedural programming can be a hurdle to later fix, bad OOP can be a nightmare. However, the information taught over the next several chapters should prevent that from being the case for you.
Defining a Class OOP programming begins with classes, a class being an abstract definition of a thing: what information must be stored and what functionality must be possible with that information?
The functionality of a User could be login, logout, change password, and more. Syntactically, a class definition begins with the word class, followed by the name of the class.
The class name cannot be a reserved word and is often written in uppercase, as a convention. They can take arguments, have default values, return values, and so on.
Attributes within classes are a little different than variables outside of classes. To make it a little more interesting, this class will be able to say Hello, world! To define a class 1.
This is a pseudo-standardized convention in many OOP languages. Script 4. This simple class will allow you to say Hello, world! This method is called sayHello. It takes one argument: the language for the greeting. This is another common convention, although not one as consistently followed as that for the class name itself. The switch prints different messages based upon the chosen language. Obviously you can easily expand this switch to include more languages, like non-Western ones.
You just need to close the HTML paragraph tag. Save the file as HelloWorld. Tip Class methods can also have a visibility, by preceding the function definition with the appropriate keyword.
The first—defining a class—you just did when you wrote the HelloWorld class. The second step is to make use of that class by creating an object or a class instance. Going back to my User class analogy, an instance of this class may be for the user with a username of janedoe. This is one instance of the User class. These are separate objects derived from the same class. They are the same in general, but different in specificity.
To create an object 1. In this page, PHP uses the defined class in order to say Hello, world! Include the class definition: require 'HelloWorld. As the definition is stored in a separate file, that file must be included here. By using require as opposed to include , the script will stop executing with a fatal error if the file could not be included and there is no point in continuing without this file.
Since the method is not being given any arguments, the greeting will be in the default language of English. Different arguments are provided to vary the result. The resulting Web page the examples will get better, I promise. Tip Class names are not case-sensitive. However, object names, like any variable in PHP, are case-sensitive. For this first example, the HelloWorld class, the emphasis is on the syntax.
But why? Having an object print one string is a very focused idea, whereas classes should be much more abstract. It also makes absolutely no sense to use all this code—and the extra memory required—for one echo statement. The HelloWorld class does succeed in a couple of ways, though. It does demonstrate some of the syntax. And it is reusable: if you have a project that needs to say Hello, world! And if you need to change it to Hello, World! Finally, this class kind of reflects the notion of encapsulation: you can use the object to say Hello, world!
The class includes a method, but it does not contain any attributes variables. This next, much more practical, example will define a class representing a rectangle. Both are initialized to 0. Both have default values of 0, just to be safe. This class is much more practical than the HelloWorld example. Calculating the area of a rectangle is simple: multiply the width times the height.
This value is then returned. If they are the same, the Boolean true is returned, indicating the rectangle is a square. Otherwise, false is returned. Save the file as Rectangle. To use the Rectangle class 1. Include the class definition: require 'Rectangle. As this method returns the area instead of printing it , it can be used in an echo statement like this. Illustrations: Many books in our library are illustrated editions and images are optimised for all screen sizes without overlapping screens.
Reference Links: Many books are created with internal clickable reference links for quick reference to Footnotes, Citations, Illustrations and Index pages. Uploaded by Kenneth Udut on February 13, Internet Archive's 25th Anniversary Logo. Search icon An illustration of a magnifying glass. User icon An illustration of a person's head and chest. Sign up Log in. Explain the digestion and absorption of carbohydrates in bullock or sheep.
How the carbohydrates are metabolised in non-ruminants? Explain the production and absorption of volatile fatty acids in rumen.
How the volatile fatty acids are metabolised in goat? Define the term carbohydrates. How the glucose is metabolised by glycolytic pathway? Glucose is helpful for lactose synthesis and fat syntheSis in the body. Justify the statement. All proteins contain carbon, hydrogen, oxygen, nitrogen and generally sulphur, many contains phosphorus. Element such as iodine, iron, copper and zinc are also occasionally present. The approximate average elementary composition of protein is as follows: Elements Average percent Carbon 50 Hydrogen 7 6.
Suppose a feed sample to be analysed yields 1. Milk nitrogen is multiplied by 6. Amino acids: Proteins are hydrolysed by enzymes, acids or alkalies into amino acids.
About 20 amino acids are commonly found as components of proteins. Amino acids have a basic amino group and an acidic carboxyl group. A pH value called isoelectric point for a given amino acid at which it is electrically neutral. Aliphatic Amino Acids a Mono amino-mono carboxylic acids Neutral amino acids 1. Glycine amino acetic acid It is simplest of the amino acids.
Valine 0. Isoleucine 0. Aspartic acid 0. Glutamic acid 0. Aromatic Amino 4cids Heterocyclic Amino Acids Non polar aliphatic amino acids 1. Name of A. Abbreviation Code 2. Glycine Gly G 3.
Alanine Ala A 4. Valine Val V 5. Leucine Leu L 6. Isoleucine Ile I 7. Methionine Met M 2. Polar uncharged A. Proline Pro P 2. Serine Ser S 3. Threonine Thr T 4. Asparagine Asn N 5. Glutamine GIn Q 6. Cysteine Cys C 3.
Aromatic side chain A. Phenyl alanine Phe F 2. Tyrosin Tyr Y 3. Tryptophane Trp W 4. Positively charged A.
Lysine Lys K 2. Arginine Arg R 3. Histidine His H 5. Negatively charged A. Aspartic acid Asp 0 2. Proteins form muscles and tissues of the body; hence it is essential for the growth and development of the body. They help in maintaining theloss of body tissues and mus- cles. They help in the formation of enzymes, hormones, anti- gen, antibody, digestive juices of the body and regulate body osmotic pressure and acid-base balance.
They help in the repair of body cells as well as for the production of new cells. They also supply energy to the body. They are essential for the formation of egg, milk protein, wool and hairs of the animals. They provide the basic cellular matrix within which the bone mineral matter is deposited.
Under condition of non-digestion and no-chances for de- naturation, the protein accumulates inside the cells and produce toxicity. Endorphins peptide are found in brain and are involved in the suppression of pain. Essential amino acid indispensable amino acid : An essential amino acid is one needed by the animal that can not be synthesized by the animal in the amounts needed and so must be present in the protein of the feed as such.
Non-essential amino acid dispensable amino aicd : A non-essential amino acid is one needed by the animals that can be formed from other amino acids by the animals and so does not have to be present as the particular amino acid in protein of the feed.
Essential amino acid Non-essential amino acids 1. Arginine Alanine 2. Histidine Aspartic acid 3. Iso-leucine Citrulline 4. Leucine Cystine 5. Lysine Glutamic acid 6. Phenylalanine Proline 8. Threonine Hydroxyproline 9. Tryptophan Serine The pig require 9 amino acids other than arginine Non protein amino acids: There are many other amino acids, which are never found as constituents of proteins but which either play metabolic roles or occur as natural products.
L- Ornithine, L- Citrulline, [3- alanine in vit. Pantothenic acid , Creatine and g- amino butyrate in brain. While the proportion may vary for different functions, it is always quite definite for any given animal performing any given set of functions. The amino acid which is present in a protein in the least amount in relation to be animal's need for that particular amino acids can be used by the animal toward meeting its essential amino acid requiremep.
It will be noted that lysine is the limiting essential amino acid of corn. Structure of proteins: The structure of proteins can be considered under four basic headings: 1. Primary Structure: Proteins are built up from amino acids means of a linkage between the a-carboxyl of one amino acid and the a -amino group of another acid.
This type of linkage is known as the peptide linkage. Large number of amino acids can be jointed together by this means with the elimination of one molecule of water at each linkage to produce poly peptides. The term primary structure refers to the sequence of amino acid along the polypeptide chains of protein. Secondary Structure: In secondary structure the peptide chain exist in the form of a right-handed -helix.
The spiral is stabilized by hydrogen bonding between the amino NH and carbonyl CO group of adjacent amino acids. Tertiary structure: It describes how the chains of the secondary structure further interact through the R-groups of amino acid residues. These interaction causes folding and bending of the polypeptide chain, the specific manner of the folding giving each protein its characteristics biological activity. If it is coiled all non- polar amino acids come in contact to form a hydrophobic centre.
Quaternary Structure: Protein poses quaternary structure if they contain more than one polypeptide chain. The force that stabilized these is hydrogen bonds and electrostatics or salt bonds formed between residues on the surface of the polypeptide chain.
Classification of proteins: Proteins may be classified into three main groups according to their shape, solubility and chemical composition. Fibrous Proteins: These proteins are insoluble and very resistant to animal digestive enzymes. They are composed of elongated, filamentous chains, which are joined together by cross linkages. They are as follows: 1. Collagens are the main proteins of connective tissues. It makeup about 30 percent of the total proteins in the mam- malian body.
Hydroxy proline is the important compo- nent of collagens. Elastin is the protein found in elastic tissues such as ten- don and arteries. It is rich in alanine and glycine 3. Keratins are the protein of hair, hoof, nails etc. These pro- teins are very rich in sulphur containing amino acid, cystiene.
Wool protein contains about 4 percent sulphur. Globular Proteins: This group includes all the enzymes, antigens and hormones that are protein. Albumin is water-soluble and heat coagulable and occurs in eggs, milk, blood and many plants. Globulins are present in eggs, milk and blood and are the main reserve protein source in seed. Histones are basic protein, which occur in cell nucleus where they are associated with DNA. They are water-solu- ble but not heat coagulable, and on hydrolysis yield large quantities of histidine and lysine.
Protamines are rich in arginine. Conjugated Proteins: Conjugated proteins are composed of simple protein combined with some non-protein substances as prosthetic group. Phosphoprotein is the protein' which on hydrolysis yields phosphoric acid and amino acids.
Casein of milk and phos- vitin of egg yolk are the best known phosphoproteins. Glycoproteins are conjugated proteins with one or more heterosaccharides as prosthetic groups. In most of the glycoproteins, glucosamine or galactosamine or both, in addition galactose and mannose may be present. Glycoproteins are components of mucous secretions which act as lubricants in many parts of the body ego ovalbumin. Lipoproteins are proteins conjugated with lipid lecithin and cholesterol. They are the main components of cell mem- branes and playa basic role in lipid transport.
Chromoproteins contain pigment as a prosthetic group. Exam pIes are haemoglobin, haemocyanin, cytochrome and flavoproteins. Nucleoproteins are compound of high molecular weight and conjugated with nucleic acid. Derived Proteins: This class of proteins includes those substances formed from simple and conjugated proteins.
Primary derived proteins: If there is a slight change in the proteins molecules such as metaproteins and coagulated proteins, they are called primary derived proteins. Secondary derived proteins: If there is a large change in protein structure, they are called secondary derived pro- teins. They are precipitated by phosphotungstic acid. The examples are proteoses, peptones and peptides. In addition many members of the vitamin B-complex contain nitrogen in their structure.
Nucleic acid: Nucleic acids are high molecular weight compounds which, on hydrolysis, yield a mixture of basic nitrogenous compound purines and pyrimidines a pentose ribose and deoxyribose and phosphoric acid. They playa fundamental role in living organism as a store of genetic information and synthesis of proteins. Nucleotide containing ribose is termed as ribonucleic acid RNA while those containing deoxyribose are referred as deoxyribonucleic acids DNA.
Nucleosides and Nucleotides: They are carbohydrates derivatives in which purines and pyrimidines found in nucleic acids are linked to a sugar in a B-N-glycosyl bond. If the nucleosides such as adenosine are esterified with phosphoric acid, they form nucleotides. Digestion of protein in non-ruminants: There is no digestion of protein in the mouth because saliva has no proteolytic enzyme.
But saliva softens the food particles, which is helpful for ingestion of protein. Digestion of proteins in the stomach: The digestion of protein start in the stomach by the action of peptic enzymes. Pepsin and gastricin are the most important peptic enzymes of the stomach. Both enzymes are most active at about pH 2 to 3, and completely inactive at pH above 5. Gastric glands secrete hydrochloric acid at a pH of about 0. These enzymes are capable of digesting protein, collagen and nucleo proteins into proteoses, peptones and polypeptides.
Digestion of proteins in the intestine: 1. Digestion of proteins by pancreatic secretions: When the proteins leave the stomach they ordinarily are in the forms of proteoses, peptones, large polypeptides and amino acids. Immediately upon entering the duodenum the partial breakdown products are attacked by the pancreatic enzymes trypsin, chymotrypsin and carboxpolypeptidases.
These enzymes are capable of hydrolyzing all the partial breakdown products of proteins to polypeptides and amino acids. Digestion of polypeptides by the epithelial enzymes of the smaIl intestine: The epithelial cells of the intestine contain several different enzymes for hydrolyzing the final peptide linkages of the different dipeptides into amino acids. So the end product of protein digestion is various amino acids.
As the microbes multiply, they synthesize protein to construct their own bodies by utilizing dietary protein and NPN substances. This microbial protein is available to the host for subsequent digestion in the lower part of the gut.
These are further fermented, by deamination to carbon dioxide, ammonia and short chain fatty acids. Ruminal proteases are mainly cell bound but may be located on the surface of the cell where the substrate is freely accessible to the enZymes.
It appears that for the bacterial proteases to act efficiently the protein must be in solution farm. Different proteins are proteolysed at different ,rates and rate of digestion of a particular protein is fairly constant. The rate of proteolysis is closely related to solubility of proteins in the water and in salt solution resembling rumen fluid.
In spite of a strong proteolytic activity in the rumen, the amino acid concentration in rumen fluid is low because of the presence of microbial deaminases, the activity of which increases with increasing protein content of the ration.
The enzyme is directly responsible for the process of deamination. Ammonia production: The ammonia in rumen liquor is the key intermediate in the microbial degradation and synthesis of protein. Parts of the ammonia produced in the rumen liquor is utilized by the rumen bacteria along with carbon moiety to synthesize the microbial proteins, and excess of ammonia is absorbed into the blood, carried to the liver and converted to urea. Some of this urea may be returned to the rumen via the saliva, and also directly through the rumen wall, but the larger part is excreted in the urine and thus wasted out.
The rumen fluid has a pronounced urease activity so that urea entering it is rapidly hydrolysed to ammonia and carbon dioxide. Increased quantity of readily fermentable sugars decrease the concentration of ammonia in the rumen thereby helping better utilization of proteins and non-protein nitrogen. Fate of ammonia: Rumen microbes for their rapid multiplication utilize considerable protein and utilize ammonia and fix it as excellent body protein composing of essential and non-essential amino acids in presence of soluble carbohydrates, particularly starch.
The rumen microbes continuously passes to the abomasum and small intestine, their cell proteins are then digested by usual gastric enzymes of the abomasum and are absorbed. Urea recycling: It is now well established that blood urea enter back into the rumen directly by transfusion through rumen wall and also indirectly through saliva.
The process would be of great value to animals on low nitrogen intake. These microbes can also make use of NPN compound and can upgrade the dietary protein of low biological values into microbial proteins of high biological values.
Therefore, it would be advantageous to feed poor quality protein and NPN compound to the ruminants. Utilization of non-protein nitrogen compound: Ruminants can utilize non-protein nitrogenous compound as a source of protein through the microorganisms. The compound which are commercially available are urea and biuret etc. First evidence of NPN compounds used in animal feed in Germany in Finger ling et al.
Urea is very common and now it has been accepted that urea can replace about 30 to 40 percent of DCP requirement. Feeding practices intended to meet these conditions include mixing urea with other feeds which should be low in rumen degradable protein and high in readily fermentable carbohydrates. It is important to avoid accidental over consumption of urea since the subsequent rapid absorption of ammonia from the rumen can exceed the ability of the liver to re-convert it to urea, hence causing the ammonia concentTation of peripheral blood to reach toxic level.
Whereas, 3 mg per rol of blood ammonia concentration is fatal. Urea does not provide the source of energy, minerals and vitamins. Urea is also deficient in sulfur containing amino acids so as a source of sulfur, 0. Derivatives of urea have been used for animal feeding with the intention of retarding the release of ammonia. Biuret is produced by heating urea.
It is colourless crystalline compound. Nitrogen in biuret is not readily utilized as protein source. Biuret is non toxic even at higher levels. Biuret is less rapidly hydrolysed than urea but requires a period of several weeks for rumen microbes to adapt to it. Adaptation becomes fast if rumen liquor innoculation with rumen liquor from an adopted rumen. However, neither biuret nor isobutylidene diurea nor urea- starch compounds have consistently proved superior to urea itself.
Uric acid, which is present in poultry faeces, is also used as ruminant feed. Urea toxicity symptoms: Nervousness, muscle tremors, difficulty in respiration, excessive salivation, bloat, tetany, convulisons and death within 2 to 3 hours are the symptoms of urea toxicity.
The drenching of glacial acetic acid cold water is the line of treatment in urea toxicity. To avoid urea toxicity, urea should be mixed properly in the feed and level of urea should be 3 percent in the concentrate mixture or 1percent in the sole ration of ruminants. Whereas BIS recommended 1 percent of urea in the concentrate mixture of ruminants. Utilization of NPN substance by non-ruminants: Non- ruminants are also able to utilize NPN compound for the synthesis of non-essential amino acids and the optimum level is 0.
But NPN substances are of little practical value for non-ruminants. It is ineffective for swine but used to some extent by mature horses on low protein diet and by hen fed diets well balanced in the essential amino acid. Protein metabolism: Dietary proteins are digested through the action of proteolytic enzymes to amino acids. These amino acids are absorbed through the small intestine into the portal blood.
Major site of absorption of amino acids is proximal2. Absorption is an active type in which transport of sodium is involved. Tripeptides are absorbed more rapidly than dipeptides, which are in turn faster than free amino acids. There is a competition for absorption within groups of free amino acids, viz, acidic, basic, neutral and imino acids but no competition between groups which suggests that slightly different mechanisms of transport exist for different chemical configurations.
They are transported to the liver and then to the systemic blood circulation. Amino acid of the blood pool serves as a major source for tissue protein synthesis. Excess of amino acids, which are not required for synthesis of tissue protein, hormones, enzymes etc. The catabolism of amino acid involves deamination whereby ammonia and a-keto-acid are formed.
The released ammonia is converted into urea or may be utilized by a-keto acid to form amino acid. Amino acid degradation take place mainly in the liver although, the kidney shows considerable activity, unlike muscular tissues which is relatively inactive.
Deamination: Separation of nitrogen from an amino acid in the form of ammonia and the detachment of non- nitrogenous residue from it, is called deamination. The nitrogen become useless during this process but the non-nitrogenous portion serves as a source of energy to the animal body. With the result of oxidative deamination of all the amino acids there is formation of ammonia and the non-nitrogenous residue keto- acid. The non- nitrogenous portion serve, as a energy source which either follow the pathways carbohydrate metabolism or fat metabolism.
Transamination: In transamination the amino group of one amino acid is transferred to the a-carbon atom of a keto acid, resulting a production of another keto acid and amino acid.
The reactions are catalysed by enzyme known as amino transferases. Transmethylation: This is the process by which methyl group is transferred from the amino acid methionine and joins the some other compounds to form choline for the formation of creatinine or phospholipid. Urea formation: One of the consequences of amino acids metabolism is the production of ammonia, which is highly toxic.
Some of this may be used in the amination of amino acids synthesis in the body. Most is excreted from t. The formation of urea which take place in the liver involve two stages both of which require an energy supply in the form of ATP. Carbamoyl phosphate 2ATP 2ADP The carbamoyl phosphate then react with ornithine to yield citrulline, which finally converted into urea and ornithine via kreb's urea cycle.
For the protein synthesis 2. For the synthesis of essential amino acids 3. As a source of energy and ammonia 4. For a special function - various important compounds are formed from amino acids which are very helpful in living system. Amino acids other than glutamate may undergo such transaminations to produce new amino acids. Activation of individual amino acids 2. Initiation of peptide chain formation 3. Chain elongation 4. Chain termination. Factor affecting protein utilization in ruminants: Various factors affect the protein utilization in ruminants, which are described below.
Dietary level of protein: Protein utilization if improved by increasing the level of protein in the diet upto the level of requirements however, more protein supplement above the requirement is not properly utilized. True protein nitrogen TPN vs.
However, NPN utilization will depends on the de- gradability of dietary protein, availability of keto acid for amino acid synthesis and minerals specially sulphur. Degradability of protein: Protein utilization is decreased as the degradability of protein in rumen is increased. The optimum ratio of rumen degradable protein RDP and rumen undegradable protein RUP in high yielding ani- mals is Degradability of different feed is different. So fish meal gives better quality protein for ruminants.
Fish meal is called naturally protected protein because it is 70 percent undegradable, which reach to lower GIT as such and provide high quality protein. Indigestible nitrogen content in diet: Indigestible nitrogen present in feed is due to damage of protein.
Excessive heating leads to browning of protein in which epsilon amino group of amino acid lysine combine with cellulose and hemicellulose to form complex which is insoluble in acid detergent solution.
So it is called acid detergent insoluble nitrogen ADIN or artifact lignin. High level of indigestible nitrogen in diet reduces the protein utilization. The classical disease of protein malnutrition of the young is kwashiorkar. The marasmus is a calorie deficient state. Amino acid deficiency: It is a condition in which the dietary supply of one or more of the essential amino acids is less than that required for the efficient utilization of other amino acids and other nutrients.
Diets are in general unlikely to be completely devoid of anyone or more amino acids but may be deficient in respect of required quantity. The amino acid, which provides the lowest proportion of the theoretical requirement, is referred to as the first limiting amino acids Lysine.
Amino acid imbalance: This term is normally restricted to circumstances where the composition of essential amino acids in the diet results in a further poorer animal performance than would be expected in case of amino acid deficiency where the effect depends on the extent of limiting amino acids. Imbalance is produced by the addition to a diet low in total protein of either the second limiting amino acid, or more usually a group of amino acid which doesn't include the first limiting amino acid.
The adverse effect on performance can be avoided by supplementation with the first limiting AA. Amino acid antagonism: Certain amino acid interferes the metabolism of other amino acids ego Lysine in excess increases the excretion of Arginine. Excess lysine also increases the activity of arginase enzyme and arginine is broken down to urea and ornithine. Antagonism differs from imbalance in that the supplemented amino acids need not be limiting amino acid.
Amino acid toxicity: The term amino acid toxicity is used when the adverse effect of an amino acid in excess cannot be over come by supplementation with other amino acids. The effect of the inclusion of the gross amounts of an individual amino acid with in a diet varies among amino acids.
Tyrosine, however when ingested in large amounts by young growing rats gives a low protein diet, not only depress severely feed intake and growth but caused severe eye and paw lesions, and in great excess is lethal. An amino acid, which is not synthesised by the animals in the required amount, is called - - - - - - - -.
Linkage between different amino acids is called - - - - 4.
0コメント