Comparative study on growth performance of broiler rabbits and biochemical parameters in New Zealand white rabbits

Introduction

Rabbits are source of low fat and high protein type meat. Thereby its production commercially is encouraged owing to traits like high prolificacy, early maturity, rapid growth rate, high genetic potential for selection, limited competition with humans for similar foods and high-quality nutritious meat [1] . Rabbits are medium sized, hopping by nature with long legs, long ears, a short tail and they require small compartments unlike cattle and other small ruminants which require a large area of land. They are easy to manage with kitchen and vegetation wastes, crop residues, organic wastes from the food industry, converting these into rich high protein meat fit for human consumption [2] . Rabbits are largely maintained by small scale farmers and rural women can also be encouraged to meet their nutritious demand and incur income. Rabbit meat is almost cholesterol free and advisable for heart patients [3] . The sodium, calcium and phosphorous contents of rabbit meat are comparatively less than other meats [4] . Rabbits are fine boned and meat to bone ratio is high that is more edible meat on the carcass when compared to chicken. Selenium in rabbit meat works as an anti-oxidant. Some types of cancer, as well as ravages of aging people can be battled with selenium [5] . On an average, the rabbit meat contains calcium (21.4 mg/100 g), phosphorus (347 mg/100 g), fat (9.2 g/100 g) and cholesterol (56.4 mg/100 g) [6] . The performance levels of these broiler rabbits of different genetic groups at the pre-weaning and post weaning ages [12] need to be established for overall improvement of the rabbit production and a profitable enterprise.

Materials and Methods

Data on pre weaning and post weaning body weights of 22 New zealand white (NZW), 31 APAU Black (BL) and 46 Flemish giant (FG) were studied during 2022-2023 in Livestock Farm Complex, College of Veterinary Science, Korutla under routine farm activities. All the does of three genetic groups were reared uniformly in galvanized iron cages. The body weights from birth to weaning age of 4 weeks at weekly intervals and at 6, 8, 10, 12 and 14 weeks of post weaning ages were recorded and were subjected to least squares analysis [7] to study the influence of genetic groups on the performance evaluation of body weight traits.

Blood sample approximately 5 ml was collected from the marginal ear vein of New Zealand White rabbits once a week for 13 consecutive weeks. The blood samples were left in slant position at room temperature for 30-60 min for serum separation. A relative centrifugation force (RCF) of 1,800 g (3,000 rpm, 15 min) was used for serum separation. After centrifugation, the supernatant plasma/serum was aspirated carefully and transferred to Eppendorf tubes for storage. The serum was kept in the fridge (4 °C) overnight prior to analysis. Changes of the biochemical and cellular components of blood samples were evaluated over the experimental period. The biochemical assay including AST, ALT, LDH, CK, glucose, BUN, creatinine, cholesterol, etc., and mineral elements were examined by automatic analyzer.

Statistical analysis

The data were statistically analyzed using the general linear model (GLM) procedure of SAS (1988). The statistical analysis model is Yij= μ + Wi+ Rj+ εij where Yij, μ, Wi, Rj and εij are dependent variable, overall mean, week effect, individual rabbit effect and random error, respectively. Differences between the means by week are measured and compared using the least square means. Extreme significance, high significance and significance are declared at P < 0.001, P < 0.01 and P < 0.05, respectively, unless specified otherwise.

Results and Discussion

There was a significant effect of genetic groups on all the pre weaning and post weaning body weights studied. [8,9,10] . Bunnies of BL genetic group recorded higher body weights [11] . Higher ADGs were observed in small litter size during pre weaning period when compared to medium and large litters [13]. Biochemical parameters including ALT, glucose, BUN, gGT, Chol, TG, ALB, lipase, and total bilirubin (T-bil) had no significant changes during this period. Only the biochemical components showing significant changes over the 13-week period are presented in Table III. All the mineral levels analyzed, except potassium (K), changed significantly over time (Table IV). ALT levels increased approximately starting from the fifth week and kept increasing up to the 13 th week. On the contrary, LDH levels reduced from the second week and then recovered at the end of this period. The CPK values were, basically, increased from the 2nd week and peaked at the middle of the entire period. Other parameters including creatinine, total protein, globulin, uric acid, and amylase concentrations, all increased at the first week, but only the A/G ratios reduced after the onset of blood collection (Table III). Serum mineral concentrations revealed similar trends as those of biochemical parameters [14] . Calcium concentrations in serum reduced after the second week. Sodium and chloride concentrations also slightly reduced at the first week and then returned to the normal levels thereafter and other serum minerals including phosphorus, magnesium, and iron, all increased after the first week of blood collection (Table IV).

Conclusion

The pre-weaning and post weaning growth traits are significantly influenced by the genetic group. Hence, selection of appropriate genetic group and proper managemental practices would be beneficial for profitable enterprise. Most of the biochemical parameters investigated showed constant values but, some selected biochemical components of the serum exhibited prominent changes during this period of study.

References

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