Effect of branched-chain fatty acids on growth of rumen microbes and digestibility and VFA production
1989
Kim, B.S. | Maeng, W.J. (Konkuk Univ., Seoul (Korea R.). Coll. of Animal Husbandry)
This experiment was attempted to study the effect of branched-chain fatty acids (BCFAs; isobutyric, isovaleric acid) and straight chain fatty acid (valeric acid) supplement on the growth of rumen microbes and energy utilization in a continuous fermentation system. With BCFAs supplement, ammonia nitrogen concentrations were increased linearly with increasing levels of hay in the diet, but no difference was observed with unsupplemented diet among hay levels. Microbial dry matter yields were lower in hay and corn ratios of 80:20 and 40:60 and were higher in hay and corn ratio of 60:40 when BCFAs was supplemented. Microbial true protein yields were some trend as microbial dry matter yields. In all hay level, dry matter digestibilities were lower in BCFAs supplement up to 9-12 hours incubation but there were no difference at 24 hours incubation. Cellulose digestibilities supplemented BCFAs were higher in hay and corn ratios of 80:20 and 60:40 but lower in hay and corn ratios of 40:60. Hay and corn ratios were influenced by fermentation rate of dry matter. It was 1.34 %/h at 80:20, 1.93 %/h at 60:40 and 1.88 %/h at 40:60 ratio without BCFAS supplement, but it was 1.62 %/h, 1.72 %/h and 2.12 %/h, respectively with BCFAS supplement. Cellulose fermentation rates were also 1.66, 2.41 and 2.17 %/h at hay and corn ratios of 80:20, 60:40 and 40:60, respectively without BCFAS supplement, but it was 2.05, 2.11 and 2.51 %/h with BCFAs supplement. Fermentation rates of cellulose were higher in hay and corn ratios of 30:20 and 40:60 but lower in 60:40 ratios with BCFAs supplement as compared with without BCFAs. Volatile fatty acid productions with BCFAs supplement were significantly higher than without BCFAs (P0.01)
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