Effect of additive fermented residues from factory on rumen fermentation and microbial population in beef cattle

Context Suboptimal beef production resulting from poor growth performance of the animals in Thailand may be due to insufficient energy and protein in the animal feed. Therefore, there is a need to find new, locally available and economical nutrient-rich feed resources. By-products from the agri-industry could be one such alternative to improve livestock feed quality. The aim of the study was to evaluate the feed intake, nutrient digestibility, rumen fermentation and microbial population of additive fermented cassava pulp with residues from noodle factory (CN). Four beef cattle at ~2–3 years of age were randomly assigned according to a 4 × 4 Latin square design. Four feed treatments had cassava pulp:residue ratios of 0:0 (NCN), 70:30 (CN1), 60:40 (CN2), 50:50 (CN3). In conclusion, feeding with CN at 60:40 might be an alternative to improve rumen fermentation efficiency, estimated energy, apparent digestibility and bacteria population. Aims The aim of the present study was to determine feed intake, nutrient digestibility, rumen fermentation and microbial population of cattle fed additive fermented cassava pulp with residues from noodle factory (CN). Methods Four beef cattle of ~2–3 years of age and of initial bodyweight of 150 ± 40 kg were randomly assigned to the following four treatments, according to a 4 × 4 Latin square design: cassava pulp:residue at ratios of 0:0 (NCN), 70:30 (CN1), 60:40 (CN2) and 50:50 (CN3) was added. All animals were fed concentrated 16% crude protein and cassava pulp–residue at 1% of bodyweight of animals. Rice straw, water and mineral salt block were offered ad libitum. Key results Feed intake and bodyweight change were not affected, while estimated energy intake and nutrient digestibilities increased (P < 0.05) after animals were fed CN2 and CN3. Ruminal pH, ruminal temperature, ammonia nitrogen and blood urea nitrogen were not altered by CN, whereas total volatile fatty acids and the proportion of propionate increased with an increasing proportion of residues from noodle factory (P < 0.05). Simultaneously, methane production was reduced by CN. In addition, bacterial population and efficiency of microbial nitrogen synthesis were increased (P < 0.05) by CN. Real-time polymerase chain reaction showed that the populations of total bacterial and F. succinogenes increased (P < 0.05), whereas populations of protozoa, R. flavefaciens and R. albus were not significantly different among the treatments. Conclusions It is concluded that feeding with CN can improve rumen fermentation efficiency, estimated energy, apparent digestibility and bacterial population. Feeding with CN2 is recommended because it showed the best response Implications Agri-industry by-products such as cassava pulp and residues from noodle factory can provide an economical alternative to improve feed quality and, hence, beef animal performace in Thailand.