This study aimed to investigate the effect of dietary supplementation with Silvafeed® ATX, vitamin E and selenium on carcass traits and blood serum metabolites of NZW rabbits under summer stress conditions.
In rabbits stress associated with exposure to high ambient temperatures results in a reduced welfare of the live animal and thus a decreased performance, especially in terms meat quality. Dietary antioxidants protect rabbit’s tissues against oxidative damage, restoring them to optimal health (Abdel-Khalek, 2013).
Forty NZW rabbits, five to six week-old, were equally distributed among four experimental dietary treatments during summer season. They were fed ad libitum following one of these diets for eight weeks: a basal diet without supplementation of potential antioxidants served as a control; the other basal diets were supplemented with vitamin E, selenium and Silvafeed® ATX respectively. Vitamin E as α-tocopheryl acetate and selenium as sodium selenite were supplied by Agrivet, Egypt. Silvafeed® ATX, composed of 85% polyphenols, among which the main ones are vescalagin and quercetin, was provided by Silvateam, Italy. Vitamin-mineral premixes were adjusted for the studied vitamin E or Selenium levels. Rabbits have been taken care of following the same managerial routine for all summer months. Five rabbits taken from each treatment were assigned to chilled carcass, liver, and abdominal fat determination as proportioned to live body weight upon slaughtering, according to Blasco and Ouhayoun (1996). Moreover, five blood samples from each tested group were assigned for serum determination of triglycerides, total cholesterol, HDL-cholesterol, LDL-cholesterol using commercial kits (Accurex Biomedical Pvt. Ltd., India). Recorded rabbitry temperatures throughout the experimental period averaged 31+2°C and the relative humidity averaged 58% during day hours (Fig. 1).
Fig. 1: Silvafeed® ATX increased FCR in rabbits during hot summer season.
Total weight gain was not significantly affected by dietary supplementation. Feed intake was higher in the control group followed by vitamin E diet compared to other treatments (P<0.05). Feed conversion ratio was improved (P<0.05) in Silvafeed® ATX group (16.1%) and selenium group (14.2%) compared to the control. The above described feeding additions had no impact on carcass traits, slaughter yield and blood serum metabolites either.
In conclusion, both the use of supra nutritional levels of Silvafeed® ATX and selenium had a positive effect on the feed conversion ratio (P<0.05) in rabbits farmed in hot temperature conditions.
Acknowledgement: I would like to express my special appreciation and thanks to prof. Ahmed AbdelKhalek, Animal Production Research Institute, Agricultural Research Centre, Egypt who has conducted the study