Effects of formic acid and corn flour supplementation of banana pseudostem silages on nutritional quality of silages, growth, digestion, rumen fermentation and cellulolytic bacterial community of Nubian black goats

The objective of this study was to evaluate the effects of adding formic acid and corn flour supplementation to banana pseudostem silages on the nutritional quality of these silages, growth, digestion, rumen fermentation and cellulolytic bacterial community of Nubian black goats fed these silages. Banana pseudostem silage was prepared either conventionally without any additives (CON) or mixed with 0.6% formic acid (F), 10% corn flour (C), or both (F+C). Four experimental diets containing 40% of the corresponding silages were designed with roughage to concentrate ratio of 50:50 (dry matter (DM) basis). A total of 48 Nubian black castrated goats (body weight (BW), (22.64±1.82) kg; 4-mon-old) were randomized into one of the four treatment groups with 12 replicates of one castrated goat per replicate for each treatment in a completely randomized design. Each group was fed on one of the four experimental diets for 40 days. A factorial arrangement of treatments of 2 (formic acid levels: 0 and 0.6%)×2 (corn flour: 0 and 10%) was adopted. Formic acid supplementation increased (P<0.05) average daily gain, as well as lactic acid, propionate and butyric acid and water-soluble carbohydrate concentrations, but decreased (P<0.05) the feed conversion rate, pH value, acetate/propionate ratio, and butyric acid concentration relative to the CON group. Corn flour supplementation increased (P<0.05) the apparent digestibility of crude protein, neutral detergent fiber, and non-fibrous carbohydrate and Fibrobacter succinogenes, Ruminococcus albus, and Butyrivibrio fibrisolvens populations, but decreased (P<0.05) the Ruminococcus flavefaciens population relative to the CON group. There were no F×C treatment interactions (P>0.05) for any of the other indices except for the apparent digestibility of non-fibrous carbohydrate (NFC) (P<0.05). The results demonstrated that adding 0.6% formic acid and 10% corn flour supplementation to banana pseudostem silages improved the nutritional quality of these silages and enhanced the growth performance of Nubian black castrated goats by improving apparent nutrient digestibility, and regulating ruminal fermentation and bacteria populations.