In vitro evaluation of total mixed ration supplemented with exogenous fibrolytic enzymes for crossbred cows.

AIM: The study was conducted to evaluate the levels of exogenous fibrolytic enzymes (EFE) on in vitro digestibilities of dry matter (DM) and organic matter (OM), total gas production (TGP), metabolizable energy (ME) content, and microbial biomass production (MBP). MATERIALS AND METHODS: The total mixed ration (TMR) was prepared using 30% each of sorghum hay and groundnut straw and 40% compound concentrate mixture to meet nutritional requirement of cow (500 kg) producing 12 kg fat corrected milk. The EFE was incorporated at 0, 40, 60, 80, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300, 320, 340, 360, 380, and 400 mg/kg TMR. The TMR substrates with different levels of EFE were in vitro incubated to ascertain their effect on digestibility, gas production, and nutritive values. RESULTS: The significantly (p<0.05) higher and optimum in vitro digestibilities of DM (63.03%) and OM (63.62%) as well as TGP (72.35 ml/500 mg TMR) were observed at supplementation of 240 mg EFE/kg TMR, while ME (7.16 MJ/kg DM) and MBP (97.63 mg/500 mg TMR) were also better. CONCLUSION: The incorporation of EFE at 240 mg/kg TMR resulted significantly (p<0.05) higher and optimum in vitro digestibilities of DM and OM. The TGP, ME, and MBP were also better. The levels of EFE 240 mg/kg TMR were found suitable for further in vivo study in crossbred cows.

Metagenome of Mehsani buffalo rumen microbiota: an assessment of variation in feed-dependent phylogenetic and functional classification.

AIM: To gain a greater understanding of the ecology and metabolic potential of the rumen microbiome with the changes in the animal diet. METHODS: Diet composed of varying proportion of green and dry roughages along with grains was given to 8 Mehsani buffaloes, and rumen metagenome was sketched using shotgun semiconductor sequencing. RESULTS: In the present study, the Bacteroidetes were found to be dominant at the phyla level and Prevotella at the genus level. The ratio of Firmicutes to Bacteroidetes was found to be higher in the solid fraction as compared to the liquid fraction. In the solid fraction of the dry roughage group, the significant increment (p < 0.05) in Bacteroidetes abundance was observed with increment of roughage concentration. At the genus level, Clostridium significantly increased with the increment in roughage concentration. A comparison of glycoside hydrolase and cellulosome functional genes revealed more glycoside hydrolase 3 encoding genes with higher fiber diet and significant difference in carbohydrate-active enzymes family composition between green and dry roughage groups of the liquid fraction. CONCLUSION: The present study provides a base to understand the modulating behavior of microbiota which can be manipulated to improve livestock nutrient utilization efficiency and for targeting the efficient catabolism of complex carbohydrate molecules as well.

Use of real-time PCR technique in determination of major fibrolytic and non fibrolytic bacteria present in Indian Surti buffaloes (Bubalus bubalis).

In the milk industry in India, buffalo breeds are most commonly used for milk production. Efficiency of fiber digestion in ruminants is critical for animal productivity. Bacteria play an important role in fiber digestion and utilization. Absolute quantification real-time PCR was used to quantify ten bacterial species in rumen fluid of Surti buffalo fed green fodder, dry roughage and compound concentrate mixture. Abundance of each target taxon was calculated as a fraction of the total 16S rRNA gene copies in the samples, using taxon-specific primers. Bacterial populations showed a clear predominance of Ruminococcus albus, which comprised 5.66% of the bacterial rRNA gene copies in the samples. However, only 0.9% to 4.24% of the bacterial rRNA gene copies were represented by the ruminal Fibrobacter succinogenes, Ruminococcus flavefaciens and Prevotella species. The proportion of rRNA gene copies attributable to Selenomonas ruminantium, Streptococcus bovis, Ruminobacter amylophilus, Treponema bryantii and Anaerovibrio lipolytica was even less abundant, each comprising < 0.11% of the bacterial rRNA gene copies. The data suggest that the aggregate abundance of the most intensively studied ruminal bacterial species is relatively low and that a large fraction of the uncultured population represents a single bacterial genus.

Methanogenic diversity studies within the rumen of Surti buffaloes based on methyl coenzyme M reductase A (mcrA) genes point to Methanobacteriales.

Methane emissions from ruminant livestock are considered to be one of the more potent forms of greenhouse gases contributing to global warming. Many strategies to reduce emissions are targeting the methanogens that inhabit the rumen, but such an approach can only be successful if it targets all the major groups of ruminant methanogens. Therefore, basic knowledge of the diversity of these microbes in breeds of buffalo is required. Therefore, the methanogenic community in the rumen of Surti buffaloes was analyzed by PCR amplification, cloning, and sequencing of methyl coenzyme M reductase (mcrA) gene. A total of 76 clones were identified, revealing 14 different sequences (phylotypes). All 14 sequences were similar to methanogens belonging to the order Methanobacteriales. Within Methanobacteriales, 12 clones (6 OTUs) were similar to Methanosphaera stadtmanae and the remaining 8 phylotypes (64 clones) were similar to unclassified Methanobacteriales. Overall, members of the Methanobacteriales dominated the mcrA clone library in the rumen of Surti buffalo. Further studies and effective strategies can be made to inhibit the growth of Methanobacteriales to reduce methane emission from the rumen which would help in preventing global warming.