Bone quality and incidence of urolithiasis in male broiler breeders fed a male or female ration.

Masters Degree. University of KwaZulu-Natal, Pietermaritzburg.

Separate sex feeding is highly practiced in breeder farms as it gives a more targeted approach to nutrition, aligning the dietary requirements with the specific needs of male and female birds. Some breeder farmers give the female ration to male breeders as it saves having two feed silos per house and eliminates the chances of females receiving the wrong feed. However, the drawback is that the female ration contains high crude protein (CP), calcium (Ca), and phosphorous (P), which is more than recommended for male requirements. A total of 40 male broiler breeders fed a male-specific ration (MM), and 40 male broiler breeders fed a female ration (MF) at depletion were acquired from KwaZulu-Natal farms. Kidney weight (KW) and kidney lesion score (KLS) from euthanised male broiler breeders were examined as an indication of urolithiasis. Tibia bone weight (BW), bone thickness(BT), bone breaking strength (BBS), tibia ash% (TA%), organic matter (OM%) and Ca/P% were quantified to assess the effects of excess CP, Ca and P on bone quality. Data collected were subjected to a two-sample t-test at a 95% confidence interval using GenStat statistical analysis software, and principal component analysis (PCA) was performed using XLSTAT. The biplots from the PCA were used to predict correlation among the variables. The study results showed that the kidney weights of MF were significantly larger compared to MM (P<0.001). Kidney lesion scores were observed in 50% MF and were significantly higher than in MM (P<0.001). Significant differences in BW, BBS, TA%, and OM% were found between MM and MF. Bone thickness, and bone Ca%, P% and Ca/P% were not significantly different among the two groups. The findings suggested that high CP, Ca and P in female feed given to male broiler breeders can negatively affect kidney and bone quality. The results indicated a significant correlation between dietary composition, bone strength and the incidence of urolithiasis. The study concluded that the nutritional composition designed for female broiler breeders may not be entirely suitable for the physiological needs of male breeders, contributing to an increased susceptibility to urolithiasis. Also, high Ca can interfere with the absorption or retention of Ca and other minerals like P, resulting in low bone quality.