Biological evaluation

A small livestock unit if attached with a mill will be of immense help. Since inspite analyzing for various mycotoxins still we face some problems, at least certain suspected ingredients can be fed at high concentrations to a set of birds and the effects could be observed.

Feed processing

Poultry feeds are generally processed in mash, crumble or pellet form. For ducks, pellet feeds or moist mash feeds are offered. The feed are proceed by grinding, mixing, pelleting and crumbling. The process is carried as follows

Grinding: Feedstuffs are usually ground with hammer mill to reduce the particle size. However ingredient like ragi is pulverized using shearing instrument as this grain is very small and the outer coating is soft, which escape grinding in the hammer mill type of grinder. The particle size of the finished product depends upon the sieve size used in the grinder. The optimal particle size is an important criterion, since challenging the gizzard is always essential, as gizzard is the best grinder, taking this point into consideration in Europe whole wheat is by-passed into the pellet mill and it is ensured that each pellet has at least half a grain of wheat. The recommended sieve size for

1.   Layer chicks, broiler starter and quails    4  mm
2.   Layer growers and broiler finisher    7 to 8 mm
3.   Layers    8 to 9 mm

Mixing: Feeds are mixed with the mixers. They are two types of mixer – vertical and horizontal type. Most of the feed millers use horizontal type of mixer. Mixing of material is done by ribbon assembly/ paddle arrangement in the mixer. Additives and supplements (vitamins, mineral and synthetic amino acids) are usually premixed in an instrument known as double cone blender and then added to the mixer. The mixing time allotted for each batch depends on the RPM of the mixer shaft. If the RPM is 24 then a mixing time of 8 minutes should be given to achieve a CV of below 10 when the salt level is taken as an indicator.

Pellet: In India, mash feed is extensively used. Pellets are used in broilers for achieving better feed conversion ratio. The cost of pelleting is increased with the increase in the electricity cost. Use of crumble feed for the first ten days in broilers has been found to improve the performance of the birds.

Supplements: Supplements are added to overcome the marginal deficiency of certain
nutrients which helps in balancing the ration and improving the overall quality of the finished feed so the full genetic potential of the birds is expressed.Supplements are nutrient added in small quantities and they are vitamins, minerals and synthetic amino acid. The commonly used synthetic amino acids are L-lysine and DL-methionine. Both fat-soluble and water-soluble vitamins needs to be necessarily incorporated in poultry feeds. Vitamins are available in the following combination AB2D3K or AB2D3EK and B1+ B6 + B12 + niacin + pantothenic acid + folic acid.

The minerals need of the birds is almost met by the supplements especially when fish  meal is not added. The trace minerals are a dd e d a s the ir sa lts. T he tr a ce mine ra l mixtures are commercially available and are a d d e d  a t  t he  r a t e  o f  1 k g/ t o n n e .  T h e combination of trace mineral is given here. The level of synthetic amino acids added  depends on the amount of this amino acids obtained from the feed ingredients. The critical amino acids which are usually deficient in the diets are lysine and methionine. Lysine is supplemented as lysine hydrochloride which contains 79% lysine and methionine is supplemented as DL-methionine which is 98% available.

Additives: Additives are non-nutrition substance added to improve the nutritive value of the feed. The additives are added depending on the specific situation. The additives added are as follows.

Toxin binders: Mycotoxins are present in most of the feedstuffs. Manufacturing feed without mycotoxins is nearly impossible, even low levels which do not affect the productivity of the bird's cause's immune-suppression due to the cumulative effects. Addition of mycotoxins binders has become essential. The commonly used binders are hydrated calcium aluminosilicate (HSCAS), activated charcoal, mannan-oligo saccharides (MOS). These are used either alone or in combination. Now certain  companies have introduced toxin destroyers which is claimed to be better than the binders.

Liver supportive/corrective's: Even though toxin binders are added some mycotoxins may be absorbed and can injure the liver hence liver supportive are added to protect the liver, hasten up the recovery and potentiate the immunity. Herbal preparations are available which contains a mixture of herbal extracts. A combination of chemicals such as choline, inositol, betaine and several B-Complex vitamins is also used.

Anti-coccidials: Coccidiosis is common in deep litter housing system of rearing, anticoccidials are used as a preventive measure. Chemicals (3,5-dinitro-toluamide (DOT), clopidol, robenidine), ionophores (salinomycin or madhuramycin, monensin), Diclauzuril, herbal preparations and a natural occurring anticoccidial (a steroidal sapogenin) are used for prevention of coccidiosis.

Antibiotics: Feed grade antibiotics are added to the feed with the objective of improving the gut ecology, improve nutrient absorption and obtain good performance with better feed efficiency. The use of feed grade antibiotics is declining as the growing concern of its residues in the product and the fear of antibiotic resistant organisms affecting the human health.

Probiotics: The Probiotics are live microbial cultures mainly of Lactobacillus group of organism. The organism in the Probiotics should be viable if used in crumble feed. The mode of action of probiotic is by competitive exclusion of harmful enteric microorganism, stimulatory effect on favorable microflora of the gut, nutrient sparing effect, improve nutrient absorption by increasing enzymatic activity and improve the absorption of nutrients by favorably modulating the villi structure . The ideal probiotic selected should have a minimum of 3 x 1010 colony forming unit per gram.

Organic acid: Weak organic acids such as formic, propionic, isobutyric, citric, sorbic, benzoic acids are used. Organic acid used for mold inhibition, reduces incidence of salmonella, E.coli in feed. It protects the birds from enteric pathogenic micro organisms and enhances growth, nutrient utilization and feed conversion efficiency

Enzymes: Non-starch polysaccharide (NSP) degrading enzymes and phytase are commonly added to the feed. The NSP degrading enzymes are able to reduce the viscosity of the gut contents and break down the cell walls, improves the functioning of the endogenous enzymes to penetrate inside the cells and digest the nutrients. Phytase enzyme breaks down the phytate phosphorus and releases the bound phosphorus and reduces the need for supplementing costly phosphorus through inorganic phosphorus supplements.

Antioxidant: Use of oils/oil rich feedstuff in the broiler and breeder feeds necessitates the addition of antioxidants to prevent rancidity of the fatty acids. Commonly used antioxidants are butylated hydroxy toluene (BHT), butylated hydroxy anisole (BHA) and ethoxyquin.