Browsing by Author "North, M. K."

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    Composition of rabbit caecal microbiota and the effects of dietary quercetin supplementation and sex thereupon
    (Universidad Politecnica de Valencia, 2019) North, M. K.; Zotte, A. Dalle; Hoffman, L. C.
    The purpose of this study was to add to the current understanding of rabbit caecal microbiota. This involved describing its microbial composition and linking this to live performance parameters, as well as determining the effects of dietary quercetin (Qrc) supplementation (2 g/kg feed) and sex on the microbial population. The weight gain and feed conversion ratio of twelve New Zealand White rabbits was measured from 5 to 12 wk old, blood was sampled at 11 wk old for the determination of serum hormone levels, and the rabbits were slaughtered and caecal samples collected at 13 wk old. Ion 16STM metagenome sequencing was used to determine the microbiota profile. The dominance of Firmicutes (72.01±1.14% of mapped reads), Lachnospiraceae (23.94±1.01%) and Ruminococcaceae (19.71±1.07%) concurred with previous reports, but variation both between studies and individual rabbits was apparent beyond this. Significant correlations between microbial families and live performance parameters were found, suggesting that further research into the mechanisms of these associations could be useful. Negative correlations with the caecal flavonoid content were found, but the latter was not affected by diet, and the effects of quercetin supplementation on the microbiota were very limited, possibly due to the absorption of the quercetin-aglycone from the gastrointestinal tract prior to the caecum. Nonetheless, Clostridiales Family XIII. Incertae Sedis was more abundant in the quercetin-supplemented rabbits (Control: 0.003±0.003%; Qrc: 0.020±0.000; P=0.005), as was the genus Anaerofustis (Control: 0.000±0.002; Qrc: 0.010±0.002; P=0.003). Serum cortisol levels were higher in females, and several microbial families differed between the sexes. Most were more abundant in female rabbits, including the most abundant, the family Eubacteriaceae (Male: 2.93±0.40; Female: 4.73±0.40; P=0.01).
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    Composition of rabbit caecal microbiota and the effects of dietary quercetin supplementation and sex thereupon
    (Universidad Politécnica de Valencia, 2019) North, M. K.; Zotte, A. Dalle; Hoffman, L. C.
    The purpose of this study was to add to the current understanding of rabbit caecal microbiota. This involved describing its microbial composition and linking this to live performance parameters, as well as determining the effects of dietary quercetin (Qrc) supplementation (2 g/kg feed) and sex on the microbial population. The weight gain and feed conversion ratio of twelve New Zealand White rabbits was measured from 5 to 12 wk old, blood was sampled at 11 wk old for the determination of serum hormone levels, and the rabbits were slaughtered and caecal samples collected at 13 wk old. Ion 16STM metagenome sequencing was used to determine the microbiota profile. The dominance of Firmicutes (72.01±1.14% of mapped reads), Lachnospiraceae (23.94±1.01%) and Ruminococcaceae (19.71±1.07%) concurred with previous reports, but variation both between studies and individual rabbits was apparent beyond this. Significant correlations between microbial families and live performance parameters were found, suggesting that further research into the mechanisms of these associations could be useful. Negative correlations with the caecal flavonoid content were found, but the latter was not affected by diet, and the effects of quercetin supplementation on the microbiota were very limited, possibly due to the absorption of the quercetin-aglycone from the gastrointestinal tract prior to the caecum. Nonetheless, Clostridiales Family XIII. Incertae Sedis was more abundant in the quercetin-supplemented rabbits (Control: 0.003±0.003%; Qrc: 0.020±0.000; P=0.005), as was the genus Anaerofustis (Control: 0.000±0.002; Qrc: 0.010±0.002; P=0.003). Serum cortisol levels were higher in females, and several microbial families differed between the sexes. Most were more abundant in female rabbits, including the most abundant, the family Eubacteriaceae (Male: 2.93±0.40; Female: 4.73±0.40; P=0.01).
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    The effect of age on the carcass composition, portion yield and proximate composition of two rabbit genetic types in South Africa
    (Universidad Politécnica de Valencia, 2017) North, M. K.; Nkhabutlane, P.; Hoffman, L. C.
    This study investigated the carcass component yields and meat proximate composition of 2 rabbit genetic types (Californian and hybrid New Zealand Red×Californian), with 5 rabbits per genetic type being slaughtered every 2 wk throughout the study period (9-17 wk) to evaluate the effect of age on these traits. Slaughter weight, reference yield, portion yield (hind leg, foreleg and fore part, as percentage of slaughter weight), meat yield, skin weight and the fat content of the meat (percentage of wet weight) increased significantly with age, while the full gastrointestinal tract, liver, head and feet decreased significantly. This is likely a reflection of the early-maturing nature of bone and viscera and later maturing nature of muscle and fat. These results indicate that delaying slaughter to 13 wk tends to improve yields for valuable carcass components. The Californian had a significantly higher total meat yield at 11 and 17 wk and higher portion meat yields at 9 (hind leg), 11 (hind leg and fore part) and 13 (foreleg) weeks than the hybrid. This was likely due to the later maturation of the hybrid and the influence of the New Zealand Red on carcass quality. It therefore appears that the Californian may be more favourable for meat production, from a carcass and meat quality perspective.
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    Growth, carcass and meat quality traits of two South African meat rabbit breeds
    (South African Society for Animal Science, 2019-10-01) North, M. K.; Zotte, A. Dalle; Hoffman, L. C.
    Rabbits could contribute to meat production in South Africa. However, little research has been done on rabbit farming in the country, including on the performance of locally available meat breeds. This study examined the meat production of the New Zealand White (NZW) and Phendula rabbit breeds. The live weights (LW) and average daily gains (ADG) of 80 (44 male, 36 female) NZW and 40 (22 male, 18 female) Phendula rabbits, housed in single-sex groups of three, were recorded from weaning (5 weeks) until slaughter (11 weeks). The slaughter weight, and carcass, organ, and carcass portion weights were recorded for 10 male rabbits and 10 females of each breed, and the physical and proximate chemical quality of the loin meat was determined. The breeds differed for the reference carcass (RC) yield (NZW: 85.3 ± 0.14%; Phendula: 84.9 ± 0.24%) and the proportions of the low-value fore (NZW: 38.6 ± 0.26%; Phendula: 37.6 ± 0.28%) and high-value intermediate (NZW: 19.6 ± 0.16%; Phendula: 20.4 ± 0.28%) parts. Females had greater LW and ADG at 11 weeks old, and reduced dressing percentages, but greater RC yields owing to lighter heads and red offal. Females also had smaller proportions of the fore part. Meat quality did not differ between the breeds or sexes. Overall, both breeds compared well to previous reports. However, they appeared to mature relatively early, as indicated by the significant sex differences, and the high carcass and meat fat content.