Lipogenic activity in goats (Blanca celtibérica) with different body condition scores

Lactational Responses of Heat-Stressed Dairy Goats to Dietary L-Carnitine Supplementation

Simple Summary

Endogenous carnitine synthesis is reduced by heat stress, and we hypothesized that carnitine supplementation would improve lipid metabolism and performance of dairy goats when exposed to high ambient temperature. In the current study, goats were exposed to thermal-neutral (15 to 20 °C) or heat stress (28 to 35 °C) conditions. In each environmental condition, goats were supplemented or not with rumen-protected carnitine in their diets. Goats exposed to heat stress experienced high body temperatures and respiratory rates, and reduced feed intake and milk production. Carnitine supplementation was transferred efficiently to blood, but had no effect on physiological or productive parameters in goats. We conclude that extra carnitine has no beneficial effects on goats’ performance and is not needed in thermal-neutral or heat stress conditions.

Abstract

Heat stress causes significant losses in milk production, and nutritional strategies are needed to alleviate its effects. Endogenous carnitine synthesis is also reduced by heat stress (HS). Carnitine plays a central role in fatty acid oxidation and buffers the toxic effects of acyl groups. We hypothesized that carnitine supplementation would make up for any carnitine deficiencies during HS and improve lipid metabolism. The objective was to evaluate rumen-protected L-carnitine (CAR) supplementation in dairy goats under thermo-neutral (TN) or HS conditions. Four Murciano-Granadina dairy goats were used in a four × four Latin square design. Goats were allocated to one of four treatments in a two × two factorial arrangement. Factors were 1) diet: control (CON) or supplementation with CAR (1 g/d); and 2) ambient conditions: TN (15 to 20 °C) or HS (0900 to 2100 h at 35 °C, 2100 to 0900 h at 28 °C). Blood free-, acetyl-, and total-carnitine concentrations increased almost three times by supplementation. Despite this efficient absorption, CAR had no effect on feed intake, milk production or blood metabolites in TN or HS conditions. Heat stress increased rectal temperature and respiratory rate. Additionally, HS goats experienced 26% loss in feed intake, but they tended to eat longer particle sizes. Compared to TN, heat-stressed goats lost more subcutaneous fat (difference in fat thickness measured before and after each period = −0.72 vs. +0.64 mm). In conclusion, supplemented L-carnitine was efficiently absorbed, but it had no lactational effects on performance of goats under thermo-neutral or heat stress conditions.

Proteome of the periovulatory oviduct and uterus of goats as related to nutritional balance

This study was conducted to evaluate the effects of different feeding levels on the proteome of oviduct and uterus tissues of hormonally stimulated goats during the periovulatory period. Forty goats were separated into four different diet groups: Diet 1.0 M (n = 11), Diet 1.3 M (n = 10), Diet 1.6 M (n = 9), Diet 1.9 M (n = 10), fed with 1.0, 1.3, 1.6 and 1.9 times live weight maintenance, respectively. After four weeks of treatment, six hormonally stimulated females per treatment group were randomly selected for collection of uterine and the oviduct tissue samples. Samples were collected after animals were slaughtered in a commercial unit. Feeding goats with 1.3 to 1.9 times more nutrients than a control group directly influenced the proteome of the oviduct and uterus, altering the expression of proteins that participate in biological processes such as apoptosis, antioxidant, and immunological activities. These events are crucial for fertilization and early embryonic survival. Expression of oviduct proteins such as Tubulin Beta 2B, Transferrin and Disulphide-isomerase A3 increased in the 1.9 M group in relation to the other feeding levels. Disulphide-isomerase A4 showed higher expression in the 1.0 M group compared to diets with higher energetic levels. As energy intake increased in the diets, there was higher expression of Alpha-1-antitrypsin and downregulation of Profilin-1 in the uterus of the goats. In conclusion, this study showed that specific proteins of the goat oviduct and uterus expressed during the periovulatory period are modified as the result of nutritional balance.

Nutritional impact on gene expression and competence of oocytes used to support embryo development and livebirth by cloning procedures in goats

Changes in the nutritional plan have been shown to affect oocyte quality, crucial to oocyte donors animals used in cloning. This study aimed to evaluate the impact of diets with increasing nutritional levels (maintenance diet=M; 1.3M; 1.6M; 1.9M) fed to goats for four weeks on follicular fluid composition, gene expression and oocyte competence used to cloning in goats. Donor females were superovulated for the retrieval of matured oocytes and physical measurements reported. After four weeks, groups receiving diets above maintenance increased thickness of subcutaneous adipose tissue and body weight, with higher values in 1.9M Group (P<0.05). Treatments did not affect follicular density, number of aspirated follicles, retrieved and matured oocytes. Animals from 1.3M group had lower (P<0.05) maturation rate (44.0%) and number of viable oocytes (65.3%) than M (68.8%) and 1.9M (76.0%). Follicular fluid glucose concentrations increased with nutritional levels (P=0.010), with a difference (P<0.05) between groups 1.9M (11.4±2.6mg/dL) and M (2.6±0.5mg/dL). The diet did not affect the expression of GDF9, BMP15, and BAX genes in oocytes, but BCL2 and apoptotic index were significantly higher (P<0.05) in the 1.3M and 1.6M groups than the other groups. Following the transfer of cloned embryos, one fetus was born live of a twin pregnancy in the 1.9M Group. The association between energy intake and oocyte quality suggests better nutritional use by oocytes when the maximum flow was used (1.9M), but the optimal feeding level in cloning still needs refinement.

EFICIÊNCIA PRODUTIVA DE OVELHAS COM DIFERENTES CARACTERÍSTICAS CONFORMACIONAIS SOB PASTEJO

Resumo: Objetivou-se avaliar a eficiência produtiva de ovelhas Corriedale de diferentes condições e estruturas corporais ao parto, mantidas em pastagem natural e/ou cultivada hibernal. Ao parto, as fêmeas foram classificadas em médias (frame = 50 a 57,5 kg) e grandes (frame = 57,6 a 62 kg) quanto ao tamanho e em média (2 a 3 pontos) ou alta (3,5 a 4,5 pontos) quanto ao escore de condição corporal. O delineamento experimental utilizado foi o inteiramente casualizado em arranjo fatorial 2 x 2 (dois grupos de estruturas corporais x duas classes de escore de condição corporal). Ovelhas com frame médio foram mais leves em relação às grandes ao parto (39,97 vs 48,16 kg, respectivamente) e ao desmame (43,10 vs 50,22 kg, respectivamente). As eficiências produtivas ao parto e ao desmame não diferiram entre ovelhas médias (46,91 e 44,24 kg) e grandes (47,83 e 45,69 kg), respectivamente. Ovelhas com condição corporal média ao parto quando comparadas com ovelhas de condição corporal alta não apresentaram diferenças significativas para eficiência produtiva ao parto (46,89 vs. 47,82 kg) e ao desmame (44,10 vs. 45,83 kg). O tamanho animal e o escore de condição corporal ao parto não influenciam a eficiência produtiva dos rebanhos ovinos sob pastejo.

Effect of body mass index at parturition on goat milk quality and yield

A hypothesis that goats in high body condition (BC) at kidding produce milk with lower free fatty acid (FFA) concentrations than do goats in poor condition was tested. Dry goats were measured for neck height and bodyweight 103 days prepartum, and body mass index (BMI) was calculated as bodyweight/height2, and used as a measure of BC. One-third of the goats with the highest BMI were allocated to the ‘high-BMI’ group, and the remaining two-thirds were allocated to ‘increased-BMI’ and ‘low-BMI’ groups. Until kidding, the high and low BMI groups were offered a low-energy diet, whereas the increased-BMI group was offered a high-energy diet. After parturition, all animals were offered the same diet. The goats that attained high BMI through feeding, but not those with inherent high BMI, mobilised body fat during early lactation, and increased milk yield. Milk FFA concentrations were reduced in multiparous goats, but not in yearling goats that had another genetic status and therefore were less susceptible to high milk-FFA concentrations.

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

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.