OSMOTIC FRAGILITY, CIRCULATING LUTEINIZING AND STEROIDAL HORMONES IN LAYING CHICKENS FED DIETARY INCLUSION OF ACETYISALICYLIC ACID (ASA)

Abstract

This experiment investigated the effect of feeding ASA on osmotic fragility, circulating luteinizing and steroidal hormones in laying hens. Four diets varying in ASA levels of 0.00%, 0.025%, 0.050% and 0.075% were formulated and fed to 192 laying chickens in a 16-week trial. The birds were allotted randomly into the four treatment diets at 48 birds per treatment with each treatment replicated four times at 12 birds per replicate. Results from blood samples collected at the end of the experiment showed significant differences in the erythrocytic fragility between the Isa Brown (IB) and Harco Black (HB) breeds. 1B was more osmotically stable to erythrocytic fragility than the HB breed at all saline concentrations. There was however no treatment or interaction effect on the erythrocytic fragility of the bird. While the four treatment diets did not show a clear—cut trend on their effects on the osmotic fragility of the red blood corpuscles (rbc), the interaction between the breed and the treatment showed an increase in osmotic stability of rbc of the HB with increase in ASA level while IB breed showed a decrease in osmotic stability of rcb with increase in the levels of ASA in the diets. It therefore meant that the IB breed would be more osmotically liable to lysis at higher ASA concentration than the HB breed. The effect of ASA on circulating pituitary and steroidal hormones revealed that there were breed differences in estradiol (E2) and testosterone concentration with the HB recording a higher (P<0.05) E2 (440.38±92.62pmol/L) versus (229.37±84.10pmol/L) and testosterone (0.68±0.1 1 nmol/L versus 0.12%0.08nmol/L) than the HB breed. There was significant treatment effect of ASA on progesterone, testosterone and E2 concentration in which these three parameters showed gradual increase with increase in dietary levels of ASA. The effects of breed versus treatment revealed that all the four parameters viz; progesterone. testosterone, E2 and cortisol differed significantly. Both IB and HB showed a corresponding increase with increase in the levels of ASA in the feed. The HB breed however gave a more consistent increase in the circulating serum values for all these parameters than in the IB breed. Conclusively, IB breed was the more osmotically stable breed in terms of the fragility of red blood corpuscles but could be more sensitive to fragility than HB breed at higher ASA concentrations. The use of ASA in the diets of laying chickens could potentiate progesterone, testosterone and estradiol synthesis and hence increase their reproductive efficiency.