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| 1 | Assessing the relationship between the rumen microbiota and feed efficiency in Nellore steers显示文摘Background:Ruminants rely upon a complex community of microbes in their rumen to convert host-indigestible feed into nutrients.However,little is known about the association between the rumen microbiota and feed efficiency traits in Nellore(Bos indicus)cattle,a breed of major economic importance to the global beef market.Here,we compare the composition of the bacterial,archaeal and fungal communities in the rumen of Nellore steers with high and low feed efficiency(FE)phenotypes,as measured by residual feed intake(RFI).Results:The Firmicutes to Bacteroidetes ratio was significantly higher(P<0.05)in positive-RFI steers(p-RFI,low feed efficiency)than in negative-RFI(n-RFI,high feed efficiency)steers.The differences in bacterial composition from steers with high and low FE were mainly associated with members of the families Lachnospiraceae,Ruminococcaceae and Christensenellaceae,as well as the genus Prevotella.Archaeal community richness was lower(P<0.05)in p-RFI than in n-RFI steers and the genus Methanobrevibacter was either increased or exclusive of p-RFI steers.The fungal genus Buwchfawromyces was more abundant in the rumen solid fraction of n-RFI steers(P<0.05)and a highly abundant OTU belonging to the genus Piromyces was also increased in the rumen microbiota of highefficiency steers.However,analysis of rumen fermentation variables and functional predictions indicated similar metabolic outputs for the microbiota of distinct FE groups.Conclusions:Our results demonstrate that differences in the ruminal microbiota of high and low FE Nellore steers comprise specific taxa from the bacterial,archaeal and fungal communities.Biomarker OTUs belonging to the genus Piromyces were identified in animals showing high feed efficiency,whereas among archaea,Methanobrevibacter was associated with steers classified as p-RFI.The identification of specific RFI-associated microorganisms in Nellore steers could guide further studies targeting the isolation and functional characterization of rumen microbes potentially important for the energy-harvesting efficiency of ruminants. | Déborah Romaskevis Gomes Lopes Márcio de Souza Duarte Alex J.La Reau Ibrahim Zuniga Chaves Tiago Antônio de Oliveira Mendes Edenio Detmann Cláudia Braga Pereira Bento Maria Eugênia Zerlotti Mercadante Sarah Figueiredo Martins Bonilha Garret Suen Hilário Cuquetto Mantovani | 2021 | Journal of Animal Science and Biotechnology2021，12，4： | 3 |
| 2 | Energetic-protein supplementation in the last 60 days of gestation improves performance of beef cows grazing tropical pastures显示文摘Background: Nutrition is one of the most important factors that affect animal performance, and it therefore also impacts on financial results in beef systems. In this way, finding the best strategy for feeding supplements is of paramount importance. Aiming to evaluate the effect of supplement feeding strategies for beef cows in the last third of gestation, two experiments were conducted. In Experiment 1, 35 pregnant Nellore cows were assigned to a completely randomized design with four treatments: control, which received no supplement; supplementation for the last 30 d of gestation(30-d; 3.0 kg/d); supplementation for the last 60 d of gestation(60-d; 1.5 kg/d); or supplementation for the last 90 d of gestation(90-d; 1.0 kg/d). All supplemented treatments received the same total amount of supplement throughout the experiment: 90 kg(20% of crude protein). A second experiment(Experiment 2) was delineated to evaluate the effects of the amounts offered in Experiment 1 on intake and metabolism. Four multiparous pregnant Nellore cows were assigned to a 4 × 4 Latin square design, with periods of15 d each.Results: There was a linear effect of the number of days of supplementation on calving body weight(BW; P < 0.05)and a quadratic effect on BW change from parturition to d 31 post-calving(P < 0.05), with cows on the 60-d strategy losing less BW post-calving. No difference was found in offspring birth BW(P > 0.10). A significant linear effect on interval from parturition to conception(P < 0.05) was observed, with the highest calving to conception interval being observed in the 90-d strategy. The level of supplementation did not affect forage intake or neutral detergent fiber digestibility(P > 0.10). Nitrogen excreted through urine tended to increase linearly with the level of supplementation(P < 0.10).Conclusion: Providing 1.5 kg of supplement during the last 60 d of gestation improves cow performance after calving, reducing the magnitude of BW lost, and reduces the number of days from calving to re-conception in the following breeding season compared to the usually recommended period of supplementation of 90 d pre-partum. | Aline Gomes da Silva Mário Fonseca Paulino Edenio Detmann Henrique Jorge Fernandes Lincoln da Silva Amorim Román Enrique Maza Ortega Victor Valério de Carvalho Josilaine Aparecida da Costa Lima Felipe Henrique de Moura Mariana Benevides Monteiro Jéssika Almeida Bitencourt | 2018 | Journal of Animal Science and Biotechnology2018，9，1： | 2 |
| 3 | Intake,digestibility and nitrogen utilization in cattle fed tropical forage and supplemented with protein in the rumen,abomasum,or both显示文摘Background: There is little information in the tropics with regard the comparative understanding of how an increased nitrogen supply in the rumen or in the intestines affects efficiency of nitrogen utilization in cattle. This study evaluated the effects of supplementation with nitrogenous compounds in the rumen, abomasum, or both on intake, digestibility and the characteristics of nitrogen utilization in cattle fed tropical forage. Four rumen- and abomasum-fistulated Nellore bulls(227 ± 11 kg) were used. Four treatments were evaluated: control, ruminal supplementation(230 g/d of supplemental protein in the rumen), abomasal supplementation(230 g/d of supplemental protein in the abomasum), and ruminal and abomasal supplementation(115 g/d protein in both the rumen and the abomasum).The basal forage diet consisted of Tifton 85 hay with a crude protein(CP) level of 78.4 g/kg dry matter. Casein was used as a supplement. The experiment was conducted using a 4 × 4 Latin square.Results: There were no differences between the treatments(P > 0.10) with regard to forage intake. The intake and total digestibility of CP increased(P < 0.01) with supplementation. The nitrogen balance in the body increased(P < 0.01) and muscle protein mobilization decreased(P < 0.01) with supplementation, regardless of the supplementation site.The efficiency of nitrogen utilization did not differ among the treatments(P > 0.10).Conclusions: The supplementation of cattle fed tropical forage with protein in the rumen, abomasum, or both similarly increased the nitrogen accretion in animal, which reflects improvements on nitrogen status in animal body. | Luana Marta de Almeida Rufino Edenio Detmann Daianyíris Gomes William Lima Santiago dos Reis Erick Darlisson Batista Sebastiao de Campos Valadares Filho Mário Fonseca Paulino | 2016 | Journal of Animal Science and Biotechnology2016，7，4： | 0 |
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