MICROALGAE AND ZINC SOURCE SUPPLEMENTATION OF BROILER BREEDER DIETS AFFECTS BROILER BREEDER SKELETAL DEVELOPMENT AND REPRODUCTION WITH TRANSGENERATIONAL IMPACTS ON OFFSPRING PERFORMANCE AND SKELETAL CHARACTERISTICS

OF DISSERTATION MICROALGAE AND ZINC SOURCE SUPPLEMENTATION OF BROILER BREEDER DIETS AFFECTS BROILER BREEDER SKELETAL DEVELOPMENT AND REPRODUCTION WITH TRANSGENERATIONAL IMPACTS ON OFFSPRING PERFORMANCE AND SKELETAL CHARACTERISTICS Leg problems and disorders are of major concern for the poultry industry and animal welfare. Previous studies suggest that it may be possible to improve skeletal characteristics through nutrition. Omega-3 fatty acids, including Docosahexaenoic acid (DHA), are essential nutrients and are known to play an important role in bone tissue development. FORPLUSTM (Alltech, Inc.) is an unextracted, whole-cell microalgae (Aurantiochytrium limacinum CCAP 4087/2) that contains 64% fat and 16% DHA. Zinc (Zn) is a trace element and essential nutrient for growth and skeletal development. Bioplex Zn (Alltech, Inc.) is a Zn proteinate that has been shown to be more bioavailable to broiler chickens compared to inorganic sources of Zn. One objective of this research was to investigate the effects of 2 dietary levels of FORPLUSTM (0% vs. 2%) and 2 dietary Zn sources (ZnO vs. Bioplex Zn) on skeletal characteristics and reproduction of broiler breeders. Breeders were maintained on these diets throughout the entire pullet and layer phases. Subsequent studies were conducted to evaluate the effect of breeder diet and offspring dietary Zn sources (ZnO vs. Bioplex Zn) and microalgae supplementation (0% vs. 1%) on offspring performance and skeletal characteristics. During the broiler breeder pullet phase, dietary supplementation of 2% FORPLUSTM increased (P<0.05) femur ash content and length. Pullet uniformity was in increased (P<0.05) by Bioplex Zn vs ZnO when microalgae was not included in the diet. Hen day production (HDP) was increased (P<0.05) by ZnO vs. Bioplex Zn supplementation during post-peak lay. During post-peak lay, hatchability and hatch of fertile eggs were improved (P<0.05) by dietary supplementation of 2% FORPLUSTM or Bioplex Zn in breeder diets, however egg weight, egg yolk weight, offspring hatch weight, and offspring body weight gain (BWG) significantly were decreased (P<0.05) by 2% FORPLUSTM. Bioplex Zn in breeder diets increased (P<0.05) growth plate zone heights, bone-specific alkaline phosphatase enzyme activity, and dimensions of offspring bones at hatch. At 3 weeks of age, offspring from breeders fed Bioplex Zn during peak-lay had greater (P<0.05) Zn content in tibia ash and bone dimensions, while offspring from breeders fed 2% FORPLUSTM vs. 0% FORPLUSTM had longer (P<0.05) femurs. No interaction effect of breeder diet and offspring diet on early performance was observed. Offspring fed diets containing Bioplex Zn vs. ZnO had greater (P<0.05) body weight (BW) and tibia dimensions at 3 wk of age. Offspring fed diets containing 1% FORPLUSTM had decreased feed conversion (feed intake: BWG), but no main effects were observed on skeletal characteristics. Overall, dietary microalgae supplementation in broiler breeder diets improved early bone development in broiler breeders, early bone development in broiler breeder offspring, and hatchability of offspring during post-peak lay, while Bioplex Zn supplementation in broiler breeder diets improved broiler breeder pullet uniformity, offspring hatchability during post-peak lay, embryonic skeletal development of offspring, and offspring bone quality. Bioplex Zn in offspring diets also improved offspring early growth performance and leg bone morphology.