Dias Ana Veronica Lino, Messana Juliana Duarte, Granja-Salcedo Yury Tatiana, Alfonso Yeison Fabian Murilo, Silva Lorrayny Galoro, Camargo Karine Dalla Vecchia, Alves Kênia Larissa Gomes Carvalho, Gonçalves Paloma Helena, Reis Ricardo Andrade, Berchielli Telma Teresinha
Department of Agricultural, Livestock and Environmental Biotechnology, School of Agricultural and Veterinary Sciences, São Paulo State University (UNESP), Jaboticabal 14884-900, SP, Brazil.
Department of Animal Science, School of Agricultural and Veterinary Sciences, São Paulo State University (UNESP), Jaboticabal 14884-900, SP, Brazil.
Life (Basel). 2023 Jul 25;13(8):1622. doi: 10.3390/life13081622.
This study aimed to evaluate the effects of supplementation with non-protein nitrogen (NPN) or ruminal undegradable protein (RUP) on intake, digestibility, and amino acid (AA) use efficiency of Nellore cattle grazing during the dry season. Eight Nellore steers (12 ± 2 months old) were used in quadruplicate Latin squares (2 × 2). The animals were placed on cv. Xaraés under continuous grazing. The treatments included the following: (1) urea supplementation (NPN) and (2) supplementation of corn gluten meal 60 (CGM, RUP). Animals supplemented with CGM showed higher intakes of dry matter (DM) supplement, total AA, essential AA, and individual AA. The supplementation did not affect the total AA digestibility, total AA flux, and the AA fluxes of microbial origin and RUP from the diet ( > 0.05). The ruminal microorganism origin flux of total AA to the duodenum was 44.5% and 52.7% for animals supplemented with NPN and CGM, respectively. Animals supplemented with CGM showed an increase in blood concentrations of isoleucine (+19.09 μmol/L), cystine (+27.29 μmol/L), and albumin (+0.11 g/dL) ( < 0.05), but this increase was not accompanied by an improvement in N use efficiency of steers ( > 0.05). RUP supplementation via CGM can be an efficient nutritional strategy to enhance the intake and absorption of AA by Nellore cattle grazing low-quality forage during the dry season.
本研究旨在评估补充非蛋白氮（NPN）或瘤胃不可降解蛋白（RUP）对旱季放牧内洛尔牛的采食量、消化率和氨基酸（AA）利用效率的影响。八头内洛尔阉牛（12±2月龄）采用四重拉丁方设计（2×2）。这些动物被置于cv. Xaraés品种的草地上持续放牧。处理方式如下：（1）补充尿素（NPN）和（2）补充玉米蛋白粉60（CGM，RUP）。补充CGM的动物对干物质（DM）补充料、总氨基酸、必需氨基酸和单个氨基酸的采食量更高。补充处理对总氨基酸消化率、总氨基酸流量以及日粮中微生物来源和RUP的氨基酸流量没有影响（P>0.05）。补充NPN和CGM的动物，十二指肠中总氨基酸的瘤胃微生物来源流量分别为44.5%和52.7%。补充CGM的动物血液中异亮氨酸（+19.09μmol/L）、胱氨酸（+27.29μmol/L）和白蛋白（+0.11g/dL）的浓度有所增加（P<0.05），但这种增加并未伴随着阉牛氮利用效率的提高（P>0.05）。通过CGM补充RUP可能是一种有效的营养策略，可提高旱季放牧于低质量牧草的内洛尔牛对氨基酸的采食量和吸收量。
