Interplay between feed efficiency indices, performance, rumen fermentation parameters, carcass characteristics and meat quality in Pelibuey lambs

Effect of differences in residual feed intake on gastrointestinal microbiota of Dexin fine-wool meat sheep

In this study, we examined the effects of different residual feed intakes (RFIs) on nutrient digestibility and the microbiota of the digestive tract of Dexin fine-wool sheep. Fifty 70-day-old Dexin fine-wool meat lambs were selected as the experimental group and fed in a single pen for 100 days. Based on their mid-term metabolic weight, 100-day average daily weight gain and daily feed intake, the male Dexin lambs were divided into a low-RFI group (13), a mid-RFI group (18), and a high-RFI group (11). Six male Dexin lambs were selected from each group to collect feces, rumen digesta and solid digesta. Rectal feces were collected from three lambs in each group. The results showed that the digestibility of dry matter and crude protein by sheep in the L-RFI group was than that in the H-RFI group (P < 0.05). Within the microbial population, f_Anaerovoracaceae, g_Christensenellaceae_R_7_group, p_Proteobacteria, and g_Roseburia were significantly correlated with RFI. Energy metabolism, metabolism of amino acids and carbohydrates, transport and catabolism, and cell migration pathways were upregulated in the L-RFI group. The differences in the microbiota of the digestive tract of sheep with different RFIs were reflected in the presence of some key bacterial genera rather than changes in the overall microbial diversity.

Compilations and updates on residual feed intake in sheep

The increasing global demand for food and the strong effect of climate change have forced animal science to advance regarding new methods of selection in search of more efficient animals in production systems. Feed consumption represents more than 70% of the costs of sheep farms, and more efficient animals can increase the farmers' profitability. One of the main measures of feed efficiency is estimated residual feed intake (RFI), created in 1963 by Robert Koch for estimation in cattle and later adapted for sheep. Animals with negative RFI values (RFI-) are more efficient than animals with positive values (RFI+), with influence on the variables of performance, carcass quality and production of enteric gases. The RFI is the most common and accepted metric of the feed efficiency trait for genetic selection, since it is independent of growth traits, unlike the feed conversion ratio. The purpose of this review article was to present updated literature information on the relationship of RFI estimates with performance measures, molecular markers, greenhouse gas production and feed efficiency, the technical aspects and physiological basis of metabolic in sheep.

- Invited Review - Translational gut microbiome research for strategies to improve beef cattle production sustainability and meat quality

Advanced and innovative breeding and management of meat-producing animals are needed to address the global food security and sustainability challenges. Beef production is an important industry for securing animal protein resources in the world and meat quality significantly contributes to the economic values and human needs. Improvement of cattle feed efficiency has become an urgent task as it can lower the environmental burden of methane gas emissions and the reduce the consumption of human edible cereal grains. Cattle depend on their symbiotic microbiome and its activity in the rumen and gut to maintain growth and health. Recent developments in high-throughput omics analysis (metagenome, metatranscriptome, metabolome, metaproteome and so on) have made it possible to comprehensively analyze microbiome, hosts and their interactions and to define their roles in affecting cattle biology. In this review, we focus on the relationships among gut microbiome and beef meat quality, feed efficiency, methane emission as well as host genetics in beef cattle, aiming to determine the current knowledge gaps for the development of the strategies to improve the sustainability of beef production.

Interaction between residual feed intake and thermal environment on performance, nitrogen balance, ingestive behavior and carcass yield of dorper lambs

Residual feed intake (RFI) is a nutritional variable used in genetic improvement programs, the relationship between the environment and the availability of energy and protein in the diet has not yet been explored. Thus, the aim was to evaluate interactions between RFI and thermal environment on performance, nitrogen balance, ingestive behavior and carcass yield of Dorper lambs receiving diets containing different concentrate levels. Dorper lambs (male, n = 64, 17.83 ± 2.43 kg and 110 ± 10 days of age) were confined individually for 40 days for RFI classification. Lambs were separated into positive RFI (n = 30) and negative RFI (n = 30) and remained confined for another 60 days. The animals were distributed in a randomized block design, with a 2 × 2 × 3 factorial scheme, with 2 confinement environments (full sun or shade), 2 groups of feed efficiency (RFI positive or RFI negative) and three diets containing different concentrate levels (30, 45 and 60%), with 5 replications in each treatment. Isolated effects of concentrate level were observed for dry matter intake and digestibility, feeding, rumination, idle and chewing times, feeding efficiency, ingested, excreted and absorbed nitrogen, and on cooling losses, hot and cold carcass yield (P < 0.05). There was an effect of environment × concentrate interaction on performance, retained nitrogen and nitrogen balance (P < 0.05). There was an effect of RFI × environment interaction on the dry matter rumination efficiency, hot and cold carcass weight (P < 0.05). Under experimental conditions, RFI did not influence the productive performance of Dorper lambs. Interactions between environment and diet indicate better performance for Dorper lamb confined in the shade and receiving a higher proportion of concentrate. Animals with negative RFI show better performance and carcass weight when confined in shade, while animals with positive RFI showed better responses to these variables when confined in full sun.

Residual Feed Intake and Rumen Metabolism in Growing Pelibuey Sheep

This study was carried out to evaluate the residual feed intake (RFI), volatile fatty acid (VFA) production and enteric methane (CH4) from growing Pelibuey sheep. In this case, 12 non-castrated Pelibuey with an initial average live weight (LW) of 21.17 ± 3.87 kg and an age of 3 months, were housed in individual pens and fed a basal diet with 16% of crude protein and 11 MJ ME for 45 days. Dry matter intake (DMI) was measured and the daily weight gain (DWG) was calculated using a linear regression between the LW and experimental period. Mean metabolic live weight (LW0.75) was calculated. RFI was determined by linear regression with DWG and LW0.75 as independent variables. Lambs were classified as low, medium, and high RFI. Feed efficiency was determined as DWG/DMI. For determining rumen pH, ammonia nitrogen concentration NH3-N), and VFA, ruminal fluid was obtained using an esophageal probe on day 40. Feed intake of low RFI lambs was approximately 16% lower (p < 0.05) while growth rate was not significantly different. Their average energy loss, expressed as CH4 production per kilogram of metabolic weight, was 17% lower (p < 0.05).