Effect of exogenous growth‐hormone‐releasing factor on blood metabolites and minerals in late maturing buffalo heifers (Bubalus bubalis)

Abstract

Previous studies have suggested that growth-hormone-releasing factor (GRF) enhanced growth and advanced puberty onset along with hormonal changes in buffalo heifers (Bubalus bubalis). However, it is not known to what extent exogenous GRF could influence blood metabolites and minerals to bring about puberty in buffalo heifers. Therefore, we planned to investigate the effect of exogenous bovine GRF (bGRF) on blood metabolites and minerals in buffalo heifers during a 3-month pre-treatment period, 9-month treatment period and 1-month post-treatment period. Six buffalo heifers were treated intravenously with bGRF (10 mug per 100 kg body weight) at 15-day interval for 9 months. Another six buffalo heifers of weight- and age-matched received requisite amount of vehicle (0.9% NaCl solution) during the same period. Exogenous bGRF enhanced (p < 0.01) plasma non-esterified fatty acids (NEFA) concentrations in treatment group when compared with control group during the treatment and post-treatment period, while plasma alpha-amino nitrogen (AAN) concentrations showed a decreasing trend (p < 0.05) in the treatment group when compared with the control group during the treatment and post-treatment periods. The plasma inorganic phosphorus (Pi) was found to be higher (p < 0.05) in the treatment group animals in comparison with the levels recorded in the control group animals during the treatment as well as post-treatment periods. However, there was no change (p > 0.05) in plasma glucose and calcium concentrations between the two groups. Plasma NEFA was found to be positively correlated with plasma growth hormone (GH); however, it was only significant for the treatment group (r = + 0.76; p < 0.05). Plasma AAN in the treatment group exhibited negative correlation with plasma GH (r = 0.72; p < 0.05), while plasma AAN and GH were recorded to be positively correlated in the control group (r = 0.47; p < 0.05). The present findings suggest that exogenous bGRF induces GH release that increases plasma NEFA and Pi and decreases AAN concentrations, which probably help to reach a certain physiological state that initiates events necessary for bringing about puberty in buffalo heifers.

Efficiency to reach age of puberty and behaviour of buffalo heifers (Bubalus bubalis) kept on pasture or in confinement

“…However, glucose levels were generally similar to those reported by a number of other authors (e.g. Haldar and Prakash, 2007, report data comparable to those obtained in Experiment I; Campanile et al, 2010 report data similar to those obtained in Experiment II). In both experiments, plasma glucose concentration was lower in FR than in C (F 1,30 = 132.6, P < 0.001 and F 1,24 = 16.0, P < 0.001 in Experiments I and II, respectively).…”

“…Elevated concentrations of both insulin and glucose in circulation are not uncommon in ruminants maintained at high nutrition levels (Campanile et al, 2010) and, in group C, may have determined a higher weight at puberty by increasing body mass and fat deposition, while being ineffective in reducing the age of puberty. Although the availability of a metabolic fuel such as glucose is assumed to be important, the exact role of glucose in the reproductive function of female ruminants has not been fully elucidated (Haldar and Prakash, 2007). Plasma total cholesterol level was lower in FR than in C in both experiments (F 1,30 = 6.8, P < 0.05 and F 1,24 = 4.5, P < 0.05 in Experiments I and II, respectively).…”

Social dominance in prepubertal dairy heifers allocated in continuous competitive dyads: Effects on body growth, metabolic status, and reproductive development

“…Dominant heifers had greater ADG than subordinate heifers, which is in agreement with larger dominant follicles at a younger age in dominant compared with subordinate heifers (Bergfeld et al, 1994;Chelikani et al, 2003). Although the exact role of glucose in the reproductive function of female ruminants is still not fully elucidated (Haldar and Prakash, 2007;Sabia et al, 2014), greater ADG and follicular growth rates are associated with increased concentrations of glucose in prepubertal dairy heifers (Abeni et al, 2000), possibly indicating a "more positive" energy status in dominant heifers that results in greater follicular development compared with subordinate heifers. Moreover, greater glucose concentrations in dominant compared with subordinate heifers can be associated with a lower age at first breeding (Brickell et al, 2009).…”

Effect of Season and Ovarian Morphology of Egyptian Buffalo on Oocyte Quality and In Vitro Maturation Rate

“…Lower reproductive pattern in buffalo related to high percentage of atretic follicles, little number of follicles, weak superovulation response, seasonal breeding, silent heat, delayed onset of maturity and long calving interval (Haldar and Prakash, 2007;. Last years, efforts have been done for increasing the reproductive pattern of these species using biotechnology (Madan et al, 1994).…”