Influence of rumen undegraded protein supplementation on intake, metabolism and ruminal microbiota of Nellore cattle grazing in the dry season

Author(s)

Ana Veronica Lino Dias

• Document type: Master's Dissertation
• Press: Jaboticabal. 2021-05-10.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agrárias e Veterinárias. Jaboticabal
• Defense date: 2021-02-26
• Advisor: Telma Teresinha Berchielli; Juliana Duarte Messana; Yury Tatiana Granja Salcedo

Abstract

This experiment aimed to evaluate the influence of supplementation with non-protein nitrogen (NNP) or ruminal undegradable protein (RUP) on intake, digestibility of nutrients, ruminal and blood parameters, use of amino acids and ruminal microbiota in Nellore cattle reared on pasture in the dry period. Eight Nellore steers with 263 ± 48.69 kg of body weight were used, allocated on pasture of Urochloa brizantha cv. Xaraés, arranged in four 2 × 2 Latin squares (2 treatments and 2 periods) balanced for residual effects. Two types of supplementation were used: mineral salt and urea; or corn gluten as a source of RUP with the addition of mineral salt. Intake and digestibility were not influenced by the type of supplement used (P> 0.05). Except for the NDF consumption, which was lower in the animals that received gluten (P = 0.0464) Animals supplemented with gluten showed a higher proportion of isoButyrate, isoValerate and Valerate of these acids in the rumen environment (P <0.05). The time influenced all ruminal fermentation parameters evaluated (P <0.05). Pmic and efficiency of microbial protein synthesis (EPBmic) were similar in animals fed different supplements (P> 0.05). The source of RUP in the supplement did not influence the diversity, wealth index and total composition of bacteria and Archaeas. Only the phylum Firmicutes was more abundant in the rumen of animals supplemented with SMU (P = 0.0188). The AA flow was not influenced by the supplement used in the experiment (P> 0.05). The flow of AA of microbial origin and the flow of AA from RUP were also not influenced by the supplement (P> 0.05), in the same way that digestibilities did not obtain significant difference (P> 0.05). Animals supplemented with SGM showed a greater amount of AAs isoleucine, threonine and cystine in the blood composition (P <0.05). The supplements affected the albumin present in the blood of animals receiving SMU, which had a lower concentration of this protein (P <0.05). The use of RUP stimulated a change in the abundance of bacteria such as Eubacterium ruminantiun, Ruminococcus.spp, Papillibacter, and Christensenellaceae, which increased the proportion of isoButyrate, isoValerate and Valerate in the rumen, and the functionality, for use of amino acids as a source of energy for the maintenance of microorganisms and a source of N for the production of Pmic through recycling. Supplementation with urea resulted in an increase in the abundance of the phylum Firmicutes. RUP supplementation in this study did not result in a greater flow of amino acids to the duodenum, but resulted in a higher content of isoleucine, threonine and cystine in the blood of the animals that received this in the diet. Although this higher blood concentration of these AA was observed, supplementation with RUP did not increase the efficiency of N use by animals fed with tropical grass pastures during the dry period. Just as supplementation with NNP did not result in an increase in AA from Pmic in the duodenum. (AU)

• FAPESP's process: 19/21280-8 - Influence of rumen undegraded protein supplementation on intake, metabolism and ruminal microbiota of Nellore cattle grazing in the dry season
• Grantee: Ana Veronica Lino Dias
• Support Opportunities: Scholarships in Brazil - Master