Composed by Dr. Ali A. Saeed
Animal resources Department
Agriculture College- Babylon University
1- Bile contains various bile salts which are important in providing an alkaline pH in the small intestine and in emulsifying fats. These salts are easily absorbed in the small intestine and rapidly recalculated back to the liver. In addition to salts, bile pigments are presented witch are responsible for its color and, ultimately, for most of the color in feces and urine.
2- Pepsin tends to attack peptide bonds involving an aromatic amino acids
(phenylalanine, tryptophan, or tyrosine), and it also has a significant action on peptide bonds involving leucine and acidic residues. Trypsin acts on peptide linkages involving the carboxyl group of arginine and lysine. Pepsin and rennin are activated by HCl; it provides a pH that is more or less optimal for pepsin activity.
3-A vast number of bacterial types may be found in the rumen, typical counts approaching numbers of 25-50 billion/ml. In addition to bacteria many species of protozoa have been identified from the rumen of animals in different situations, but typical values to be expected are on the order of 200,000 – 500,000/ml (0.2 - 0.5 million / ml). Most if not all protozoal species ingest rumen bacteria and many also ingest food particles. Considerably lower concentration of flagellated protozoa is some times found. In addition, relatively large counts of phages (bacterial viruses) have been noted in recent years. Yeasts some times occur in large numbers, but not with great regularity. The fate of rumen microorganisms is that, eventually, they will pass into the abomasums and intestines where they are digested by the host animal.
4- Data on sheep and cattle indicate that about 2/3 of digestible organic matter and energy disappear from the fore stomach, the remainder being digested in the intestine. The more fibrous carbohydrates, are being digested to a somewhat greater extent (65- 90 % of total digestion) in the forstomach. Digestibility of N is quite variable, but is relatively more important in the small intestine; this is a reflection of passage of large amounts of microbial proteins into the small intestine.
5- The color of feces is from plant pigments and stercobilinogen produced by bacterial reduction of bile pigments. The odor is from aromatic substances, primarily indole and skatole, which are derived from deamination and decarboxylation of tryptophan in the large intestine.
6- Urine represents the main route of excretion of nitrogenous and sulfurous metabolites of body tissues. In addition it is usually the principal route for excretion of some of the mineral elements, particularly Cl, K, Na and P. Urine is, essentially, an aqueous solution of these various components with minor amounts of pigments and sloughed cells from the urogenital tract. The color is primarily due to urochrome, a metabolite of bile pigments complexed with peptide. The urine from ruminants is usually basic, being in the pH range of 7.4- 8.4, the basic reaction is characteristic of herbivorous animals because of the relatively large amounts of Na and K ions found in vegetation. Urine is usually in the acidic range in monogastric species. Excess nitrogen metabolized to ammonia in rumen, then ammonia metabolized in liver to urea which is excreted by urine. Saliva is another source of urea.
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