Residual feed intake and hematological and metabolic blood profiles of lle de France lambs

Abstract

-The objectives of this study were to estimate the phenotypic correlations of residual feed intake (RFI) and gross feed efficiency (GFE) with hematological and metabolic blood profiles of lambs and to determine the differences for these traits in animals of different RFI classes. Twenty Ile de France male lambs, 115±8 days of age and 31.3±4.1 kg of body weight (means ± SD), were individually housed and their dry matter intake was measured over 65 days. They were weighed every 13 days to determine the average daily weight gain and two blood samples were collected at the last two weighings (at 07h30) for analysis of blood variables. The animals were divided into two classes: negative RFI (most efficient: <0.5 SD below the mean; n = 6) and positive RFI (least efficient: >0.5 SD above the mean; n = 8). There were associations among RFI and the serum metabolic variables for albumin (r RFI = 0.74) and creatinine (r RFI = −0.45) and between GFE and serum albumin (r GFE = −0.70). Less efficient animals as measured by RFI had higher serum albumin and lower creatinine levels and showed a tendency to have a greater concentration of total plasma protein. Other serum biochemical parameters were not correlated with GFE and RFI, and no differences between RFI classes were found. There was a correlation between the percentage of eosinophils and RFI (r RFI = −0.65), and such more efficient animals had a higher proportion of these cells and a trend to have a lower percentage of monocytes. This study provided evidence indicating associations between RFI and protein metabolism, as reflected by the serum albumin and creatinine. The hematological findings suggest that RFI is related to susceptibility of lambs to stress and should provide a basis for further research in this regard.

Feed utilization, blood metabolites and ingestive behavior in Sahiwal calves divergently selected for low and high residual feed intake

“…Plasma creatinine level was negatively associated with fat depth (CLARKE et al, 1996) and was found to be negatively correlated with RFI (HERD and ARTHUR, 2009). Similar to the findings of the present study, PAULA et al (2013) and observed a negative correlation (r = -0.45) between RFI and the mean concentration of serum creatinine, and a comparison of the two RFI groups showed significant differences for this variable. However, no differences in the levels of blood creatinine between the low and high RFI groups were observed by SHARMA et al (2016) andBOSE et al (2014) in Murrah buffalo calves, or by NASCIMENTO et al (2015) in Nellore cattle.…”

Feed efficiency and the liver proteome of fattening lambs are modified by feed restriction during the suckling period

“…In the livestock sector, this could be achieved by reducing the feed to gain ratio or 'feed conversion rate' (FCR, defined as the amount of feed needed to produce one unit of animal product) which would also reduce the environmental impact of animal farming. As far as lamb production is concerned, a decrease of up to 15% in dry matter intake (DMI) between efficient and inefficient animals to reach a similar target body weight has been demonstrated (de Paula et al, 2013).…”

Efecto de la alimentación en la fase de lactancia sobre la eficiencia de utilización del alimento en el período posdestete y su relación con la microbiota del tracto digestivo, el estatus oxidativo e inmunológico en el ganado ovino = Effects of early feed restriction during the post-weaning period on feed efficiency, gastrointestinal microbiota, anti-oxidant status and immunity parameters of lambs

“…El RFI se obtiene a partir de la diferencia entre el consumo observado y el consumo estimado con el modelo estadístico, de modo que los animales con menor valor RFI son considerados más eficientes porque ingieren menos alimento que el que podría esperarse en régimen ad libitum para un ritmo de crecimiento determinado. En ganado ovino se ha comprobado que los corderos con menor valor RFI (y, por tanto, más eficientes) consumen entre un 11 y un 18% menos de materia seca en el periodo de cebo y tienen una ADG similar a los de mayor RFI (Sharifabadi et al, 2012, de Paula et al, 2013, Liang et al, 2017, Zhang et al, 2017. Teniendo en cuenta que el cebo de corderos ligeros tiene una duración aproximada de 50 días, reducir en 150 g el consumo medio diario de cada cordero manteniendo la misma ADG permitiría ahorrar 7,5 kg de alimento en todo el periodo, disminuyendo significativamente los costes de producción derivados de la alimentación.…”

“…Los cambios en la composición corporal pueden afectar a la eficiencia alimentaria porque el aumento de peso basado en la deposición de proteína es más eficiente que el obtenido a partir del depósito de grasa. Se ha descrito que los corderos y terneros con menor RFI presentan mayores concentraciones sanguíneas de creatinina (Richardson et al, 2004, Lawrence et al, 2012, de Paula et al, 2013, Fitzsimons et al, 2013, un producto final de la degradación de la creatina que sirve como indicador de la masa muscular . La creatinina está correlacionada negativamente con el grosor de la grasa del lomo ovino (Clarke et al, 1996), por lo que el menor depósito de tejido adiposo observado en el lomo de los corderos más eficientes (Zhang et al, 2017) se encuentra en consonancia con las mayores concentraciones sanguíneas de este metabolito.…”

“…En cambio, hormonas con roles importantes en el metabolismo y la composición corporal, como la leptina, la insulina o el factor de crecimiento insulínico tipo I (IGF-I), no parecen estar asociadas con el RFI en la especie ovina (Zhang et al, 2017), al igual que se ha observado en terneros (Lawrence et al, 2012). Parámetros bioquímicos como la glucosa, los triglicéridos o la proteína total tampoco han demostrado ser predictores fiables del RFI, o al menos no se han obtenido resultados consistentes entre los estudios publicados hasta el momento (Rincón-Delgado et al, 2011, de Paula et al, 2013.…”