Effect of supplementary choline on the performance of broiler breeders fed on different energy sources

1. Laying performance, egg quality, fertility and hatchability, and fat deposition in liver and abdomen were recorded in broiler breeders (29 to 48 weeks of age) fed on diets containing perarl millet (Pennisetum typhoides) (PM), broken rice (BR) or yellow maize (YM) (600 g/kg diet). Constant ratios of metabolisable energy (ME) to other nutrients were maintained in all the diets. Food grade choline chloride (50%) was added to the diets at 3 concentrations (0, 760 and 1,520 mg/kg). Each diet was offered to 3 replicate groups of 15 birds (12 hens and 3 cockerels), maintained in deep litter pens, to provide 1.46 MJ ME/bird/d. 2. Neither the source of energy nor dietary choline content had any influence on hen-d egg production, fertility or hatchability. Food efficiency and egg weight were significantly reduced in BR-fed groups compared to those fed on the other energy sources. 3. The efficiency of energy and protein utilisation increased and liver fat content was decreased significantly by dietary choline supplementation. 4. Haugh unit score, egg shell weight, liver weight and intestinal weight were not influenced by either supplementary choline or the source of energy. However, the yolk colour index was significantly reduced in PM- or BR-fed groups compared to those fed on the maize-based diet. 5. Deposition of abdominal fat was significantly greater in BR-fed birds compared to those fed on the YM-based diet, while liver fat content was significantly greater in the birds fed on the PM-or BR-based diets than those based on YM. Although supplementation of the diet with choline had no influence on abdominal fat deposition, liver fat content was significantly reduced in birds given diet containing 760 mg supplemental choline/kg diet. 6. The present study indicates that PM or BR can be used as principal energy sources in place of YM in broiler breeder diets without affecting egg production, fertility or hatchability. Liver fat content can be reduced by adding choline at 760 mg/kg to diets based on different energy sources.     

Investigation of the effect of Equivac® HeV Hendra virus vaccination on Thoroughbred racing performance

Objective

To evaluate the effect of Equivac® HeV Hendra virus vaccine on Thoroughbred racing performance.

Design

Retrospective pre‐post intervention study.

Methods

Thoroughbreds with at least one start at one of six major south‐eastern Queensland race tracks between 1 July 2012 and 31 December 2016 and with starts in the 3‐month periods before and after Hendra virus vaccinations were identified. Piecewise linear mixed models compared the trends in ‘Timeform rating’ and ‘margin to winner’ before and after initial Hendra virus vaccination. Generalised linear mixed models similarly compared the odds of ‘winning’, ‘placing’ (1st–3rd) and ‘winning any prize money’. Timeform rating trends were also compared before and after the second and subsequent vaccinations.

Results

Analysis of data from 4208 race starts by 755 horses revealed no significant difference in performance in the 3 months before versus 3 months after initial Hendra vaccination for Timeform rating (P = 0.32), ‘Margin to winner’ (P = 0.45), prize money won (P = 0.25), wins (P = 0.64) or placings (P = 0.77). Further analysis for Timeform rating for 7844 race starts by 928 horses failed to identify any significant change in Timeform rating trends before versus after the second and subsequent vaccinations (P = 0.16) or any evidence of a cumulative effect for the number of vaccines received (P = 0.22).

Conclusion

No evidence of an effect of Hendra virus vaccination on racing performance was found. The findings allow owners, trainers, industry regulators and animal health authorities to make informed decisions about vaccination.     

Production Performance,Serum/Yolk Cholesterol and Immune Competence of White Leghorn Layers as Influenced by Dietary Supplementation with Probiotic

An experiment was conducted to measure the influence of a dietary probiotic on the production performance, the concentrations of cholesterol in the serum and yolk and immune competence in White Leghorn layers from 25 to 72 weeks of age. One hundred and twenty commercial White Leghorn layers, aged 24 weeks, with an average of 62% hen-day egg production, were equally and randomly distributed into three groups, with eight replicates of 5 birds in each. The birds were reared in individual laying cages. They were placed on one of three dietary treatments: basal, or basal with probiotic supplementation at a rate of 100 or 200 mg/kg feed. The addition of probiotic significantly increased the egg production, shell weight, shell thickness and serum calcium, and reduced the concentrations of cholesterol in the serum and yolk. However, no differences in these traits was observed between the groups receiving 100 or 200 mg probiotic. Feed conversion, egg weight, serum phosphorus and serum alkaline phosphatase activity were not influenced by supplementation with probiotic. Antibody production in response to the inoculation of sheep red blood cells and the cutaneous basophilic hypersensitivity (CBH) responses to inoculation with phytohaemagglutinin did not differ significantly among the dietary groups at either 24 or 40 weeks of age. The antibody titre was significantly higher in the groups supplemented with probiotic at 64 weeks of age. The addition of 100 mg/kg of probiotic in the diet significantly increased the CBH response at 64 weeks of age.