Manipulations of Rumen Fermentation for Improving Production in Animals

INTRODUCTION
Rumen is a natural fermentative anaerobic system which should be manipulated essentially by altering the composition of rumen microflora. There is ample scope to manipulate the rumen by feeding local plants or tree leaves or agro industrial byproducts to defaunate the animals for improving its productivity. Introduction of naturally occurring microorganism from digestive system of one species to another species for efficient degradation of plant toxins as well as for efficient utilization of nutrients will be one of the major thrust area in near future for rumen manipulation. Genetically manipulation of rumen microorganism for efficient ruminal fermentative digestion has an enormous biotechnological potential. However in tropical countries like India, more emphasis is given for manipulating the rumen to increase cellulolytic activity for efficient utilization of low grade roughage.

METHODS OF RUMEN MANIPULATION

1. Genetic manipulation: Increase of desired activities such as cellulolysis and detoxification or reduction of undesirable activities such as proteolysis, deamination and methanogenesis occurs. New species or strains of microorganisms e.g. Fibrobacter succinogens are introduced into the gut. The genes which have been cloned in Escherichia coli are endoglucanase, xylanase, β-glucosidase and amylase glutamine synthetase from the donor source of Bacteroides fibrisolvens, Ruminococcus flavefaciens, Fibrobacter succinogenes, Neocallimastix frontalis, Streptococcus bovis, etc.

2. Non-genetic manipulation: Use of live microbial cultures (probiotics) is being tried now-a-days as natural feed additives for enhancing rumen metabolic activity and thereby overall animal production. Supplementation of different probiotics (fungi/yeast and bacteria) results in improved nutrient status and productivity of the ruminants under certain conditions. The commonly used probiotics for animal feeding are broadly divided into two categories i.e., bacterial and yeast origin. The bacterial origin are Bacillus licheniformis, Lactobacillus casei subtilis, Lactobacillus cellobiosus, Bifadobacterium adolescentis, Lactobacillus delbrueckii, Bifadobacterium animalis, Lactobacillus fermentum, Bifidobacterium bifidus, Lactobacillus lactis, Bifadobacterium infantis, Lactobacillus plantarum, Bifadibacterium longum, Lactobacillus salivarius, Bifidobacterium peudolongum, Lactobacillus sporogens, Bifidobacterium suis, Lactobacillus reuteri, Bifadobacterium hermophilum, Streptococcus intermdius, Lactobacillus acidophilus, Lactobacillus bulgaricus and Streptococcus thermophilus The probiotics of yeast origin are Lactobacillus brevis, Aspergilus oryzae and Saccharomyces cerevisiae.

3. Properties of Microbes as Probiotics: Microbes as probiotics are resistant to low pH and bile salt. They produce lactate and other antimicrobial agents. Microbes are a normal inhabitant of the gut in the target animal species. They are able to survive, colonize and multiply at a faster rate in the gut. Viable product can be formed at industrial scale for its commercialization. They are stable and viable during long storage and field conditions. They must produce beneficial effect in host animals.

4. Protected Nutrients: Rumen undegradable proteins (RUPs) in maize are poorly fermented in the forestomach but are readily digested in abomasum and intestine. Denaturation of protected nutrients is done by formalin.

5. Protected Enzymes: Dietary supplements containing exogenous enzymes such as cellulases and hemicellulases have favourable attraction of fostering favourable microbial cultures in the rumen.

6. SELECTIVE ANTIBIOTICS IN FEED: The ionophore monensin selectively suppresses the methane-producing bacteria and the amount of wasted energy.

7. Concentrate-Enriched Diets: When the energy and protein requirements of domestic ruminants are increased to satisfy productive situations, part of the roughage from the diet is replaced by feeding grain and grain-based concentrates.

8. Buffers: Buffers and alkali are used on some farms where acidic feeds like silage and overfeeding of concentrates are known to cause low pH ruminal conditions and reduce productivity.

ADVANTAGES OF RUMEN MANIPULATION
Rumen manipulation causes growth promotion. It improves feed conversion efficiency. Manipulation of rumen causes better absorption of nutrients by control of gut epithelial cell proliferation and differentiation. It improves the metabolism of carbohydrate, calcium and synthesis of vitamins.

CONCLUSION
In livestock, the conditions of rumen manipulation are after birth to encourage the early establishment of beneficial rumen microflora, following antibiotic treatment, in the presence of enteric pathogen such as E. coli, Salmonella, Coccidia, etc. and during environmental or managemental stress. In calves, it is essentially done by the administration of probiotics. These are mostly effective under the circumstances like after birth, before and after transportation, at weaning, following over eating and antibiotic administration. In adult cattle, ketosis, antibiotic treatment, bloat and difficult calving are the probable conditions. Thus manipulation of rumen fermentation is essential for the increasing productivity of livestock.