The effects of metabolizable energy intake on body fat depots of adult Pelibuey ewes fed roughage diets under tropical conditions

Abstract

The objective of this work was to evaluate the effect of metabolizable energy intake (MEI) on changes in fat depots of adult Pelibuey ewes fed roughage diets under tropical conditions. Eighteen 3-year-old Pelibuey ewes with similar body weight (BW) of 37.6 ± 4.0 kg and body condition score (BCS) of 2.5 ± 0.20 were randomly assigned to three groups of six ewes each in a completely randomized design. Ewes were housed in metabolic crates and fed three levels of MEI: low (L), medium (M), and high (H) for 65 days to achieve different BW and BCS. At the end of the experiment, the ewes were slaughtered. Data recorded at slaughter were: weights of viscera and carcass. Internal fat (IF, internal adipose tissue) was dissected, weighed, and grouped as pelvic (around kidneys and pelvic region), omental, and mesenteric regions. Carcass was split at the dorsal midline in two equal halves, weighed, and chilled at 6°C during 24 h. After refrigeration, the left half of the carcass was completely dissected into subcutaneous and intermuscular fat (carcass fat). Dissected carcass fat (CF) of the left carcass was adjusted as whole carcass. At low levels of MEI, proportion of IF and CF was approximately 50%; however, as the MEI was increased, the proportion of IF was increased up to 57% and 60% for M and H, respectively. Omental and pelvic fat depots were those which increased in a larger proportion with respect to the mesenteric fat depot. Regression equations between the weight of each body fat depot and BW had a coefficient of determination (r (2)) that ranged between 0.37 for mesenteric fat and 0.87 for CF. The regression with BCS had a r (2) that ranged between 0.57 for mesenteric and 0.71 for TBF. BW was the best predictor for TBF, CF, omental fat, and pelvic fat; whereas, BCS was better than BW in predicting IF and mesenteric fat. Inclusion of both BW and BCS in multiple regressions improved the prediction for all fat depots, except for pelvic fat, which was best estimated by BCS alone. The greater slope of the regression for the pelvic fat depot equation, relative to TBF (1.40), EBW (4.02), and BCS (2.36), suggested that pelvic fat has a greater capacity to accumulate and mobilize fat. These results indicated that adult Pelibuey ewes seem to store a considerable proportion of absorbed energy in the IF depots rather than in the carcass.

Determination of Energy and Protein Requirements of Sheep in Indonesia using a Meta-analytical Approach

“…Higher CP requirement obtained in this study probably is a reflection of the difference between tropical and temperate sheep breeds in which the tropical breed has generally lower growth potential (Chay-Canul et al, 2011) as previously described. High environmental temperature in the tropics may also explain such high CP m and CP g requirements obtained in the current study.…”

“…On the contrary, our database was developed by using sheep genotype of tropical origin and thus apparently more appropriate with the recommendation of Kearl (1982). Tropical genotypes generally are not selected for muscle deposition and, hence, tend to be fatter as compared to those of temperate genotypes (Chay-Canul et al, 2011). In consequence, tropical genotypes require more energy for ADG than the temperate genotypes.…”

Requerimientos energéticos de ovinos de pelo en las regiones tropicales de Latinoamérica. Revisión

“…In adult animals, when energy intake is lower than that required for suministro de energía insuficiente se refleja en lento crecimiento, mayor edad a la pubertad, reducción en fertilidad, menor producción de leche y una mayor susceptibilidad a los nematodos. En animales adultos, cuando la ingesta energética es menor que la necesaria para el mantenimiento, el animal utiliza sus reservas corporales de energía (13) , especialmente de grasa, y cuando esto ocurre en exceso, enfermedades metabólicas como cetosis pueden surgir. Al final de la gestación y principio de la lactancia, también se puede presentar un desequilibrio energético, que induce al animal a utilizar sus reservas energéticas corporales para producción de leche (14) .…”

Evaluación del consumo de energía metabolizable sobre el contenido energético de la canal en borregas Pelibuey

“…El consumo total de MS fue diferente ) para B, M y A respectivamente (20) . El CEM promedio durante el experimento fue 0.247, 0.472 y 0.532 MJ/ kg PV 0.75 /día para los niveles B, M y A respectivamente (20) . El cambio diario de peso en las ovejas Pelibuey adultas fue de -106, -22 y 30 g/día para los niveles B, M y A respectivamente (20) .…”

“…El CEM promedio durante el experimento fue 0.247, 0.472 y 0.532 MJ/ kg PV 0.75 /día para los niveles B, M y A respectivamente (20) . El cambio diario de peso en las ovejas Pelibuey adultas fue de -106, -22 y 30 g/día para los niveles B, M y A respectivamente (20) . Los pesos de la canal fría y caliente fueron superiores para el nivel A con relación al B (P<0.05), sin embargo, estos no difirieron del nivel de alimentación M (Cuadro 3).…”