Growth, metabolic status and ovarian function in buffalo (Bubalus bubalis) heifers fed a low energy or high energy diet.
ABSTRACT The aim was to establish the capacity of buffalo heifers to adapt their metabolic requirements to a low energy diet. Murrah buffalo (Bubalus bubalis) heifers undergoing regular estrous cycles were randomly assigned by age, live weight (LW) and body condition score (BCS) to a high energy group (HE, 5.8 milk forage units (MFU)/day, n=6) or low energy group (LE, 3.6 MFU/day, n=6). Circulating concentrations of metabolic substrates, metabolic hormones and reproductive hormones were determined weekly for 19 weeks. Ovarian follicular characteristics and oocyte parameters were also ascertained weekly. Heifers fed the LE diet had a better dry matter conversion than heifers fed the HE diet and the calculated daily energy provision was negative for heifers fed the LE diet (-0.248 MFU) and positive for heifers fed the HE diet (5.4 MFU). Heifers fed the HE diet had an increase in 50 kg LW over the duration of the study whereas LW remained constant for heifers fed the LE diet. The BCS of heifers fed the HE diet (4.2) was greater (P<0.05) than the BCS for heifers fed the LE diet (3.4). Heifers fed the HE diet had greater (P<0.05) circulating concentrations of metabolic substrates (glucose, total cholesterol and HDL cholesterol) and metabolic hormones (insulin, glucagon, leptin and T3) compared with heifers fed the LE diet. There were no significant differences in circulating reproductive hormones between the two groups of heifers. Ovarian follicular characteristics were similar for the two groups of heifers while heifers fed the LE diet tended to have oocytes of reduced quality compared with heifers fed the HE diet. The most notable finding was that heifers fed the LE diet had a negative calculated daily energy provision but were able to maintain LW and reproductive activity. It was concluded that buffalo heifers may potentially have the capacity to undergo metabolic adjustment and reduce their energy requirements when dietary energy is limiting. This adaptive capacity would explain why buffaloes remain productive in environments that are limiting to other ruminants.
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ABSTRACT: This study assessed the interactive effects of carbohydrate type (fibre vs starch) and fatty acid (FA) supplementation (0% vs 6% calcium soaps of palm oil FA) on the post-fertilisation development of oocytes recovered from low and moderate body condition score (BCS) heifers. A secondary objective was to compare the FA composition of plasma to that of granulosa cells (GCs) and cumulus-oocyte complexes (COCs) from these animals, and to relate these findings to the developmental potential of oocytes. Plasma, GCs and COCs were recovered from 32 heifers on day 5 of a synchronised oestrous cycle for FA analyses. Oocytes were also recovered on days 10 and 15 of the same cycle after short-term ovarian stimulation (FSH + GnRH), and matured, fertilised and cultured to the blastocyst stage in vitro. High levels of dietary starch increased (P < 0.01) plasma insulin but, together with dietary FA, reduced (P < 0.05) blastocyst yields in low, but not in moderate, BCS heifers. Diet-induced alterations to the FA content of plasma were less apparent in GCs and COCs. In summary, although dietary lipids increased the FA content of COCs, the selective uptake of saturated FAs at the expense of mainly polyunsaturated FAs within the follicular compartment ensured that the FA composition of COCs was largely unaffected by diet. However, the concentration of saturated FAs within COCs was inherently high, and so further increases in FA content may have impaired post-fertilisation development. The data establish a robust nutritional framework for more detailed studies into the mechanistic effects of dietary composition on the post-fertilisation developmental potential of oocytes.Reproduction (Cambridge, England) 03/2006; 131(2):247-58. · 3.56 Impact Factor
Article: A radioimmunoassay of thyroxine.Journal of Clinical Endocrinology & Metabolism 12/1971; 33(5):865-8. · 6.43 Impact Factor
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ABSTRACT: This study was undertaken in order to evaluate the effect of oocyte source (live animals and abattoir ovaries) on subsequent embryo development in buffalo (Bubalus bubalis). Cow ovaries were also collected as oocyte donors for in vitro embryo production (IVEP). Three hundred thirty-eight oocytes were recovered by ovum pick up (OPU, Group A) from 8 pluriparous buffalo cows, while 1127 and 1457 oocytes were aspirated, respectively, from buffalo (Group B) and bovine (Group C) slaughterhouse ovaries. Cumulus enclosed oocytes (COCs) suitable for IVEP were in vitro matured (IVM), fertilized (IVF) and cultured (IVC) to the tight morula (Tm) and blastocyst (Bl) stage. Within buffalo species Group A had a higher Bl yield (29.7 % versus 19.9%; P<0.05) and a lower proportion of embryos arrested at Tm stage (11.1% versus 22.3%; P<0.05) than Group B. Within slaughterhouse groups cattle oocytes had a higher cleavage rate (83.9% versus 64.8%; P<0.05) and yielded 49.2% more blastocysts than buffalo. However, when data are related to the total number of cleaved oocytes, only 13.7% more blastocysts were produced in cattle than in buffalo.In conclusion, in buffalo species the source of oocytes significantly affected post-fertilization embryo development, as demonstrated by the higher Bl yields derived from OPU-derived oocytes.A higher overall IVEP efficiency, mainly related to the higher cleavage rate, was recorded in cattle compared with buffalo when ovaries from an abattoir were used as oocyte donors.Theriogenology 03/2003; 59(5-6):1123-30. · 2.08 Impact Factor