The effects of dietary crude protein on fertility of broiler breeder males.
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Date
2010
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Abstract
Fertility of Broiler Breeders (BBs) has been researched over many years with inconclusive
findings. Genetic selection and improvements in growth traits have had negative effects on
fertility of BB. One explanation is related to overweight birds, resulting in the inability of birds
to copulate successfully, with no cloacal contact. The requirements of CP for egg production in
BB females have been quantified, but there is less literature on how CP affects fertility in male
BBs. The objective of this experiment was to investigate the effects of feeding BB males
different dietary CP intakes (10.4, 12.4, 14.2, 17.8, 19.3 and 20.1 g CP/bird/day) on fertility in
flocks with natural mating and in birds that were artificially inseminated (AI). Results showed
that birds consuming 10.4 and 12.4 g CP/bird/day resulted in weight loss (between 24.9 and
23.6% and 26.5 and 22.4% below target BW) over the 29 weeks of the experimental period in
both natural mating and individual pens respectively. Intakes of higher protein content (17.8-
20.1 g CP/bird/day) however resulted in BW gain over the experimental period. Hatch
percentage across all CP intakes throughout the duration of the study was found to be high,
ranging between 75- 100 and 80-95 % in AI and naturally mated birds respectively, and not
affected by CP intakes. Similar results for predicted fertility using the methods published by
Brillard & Antoine (1990) and Wishart (1997) were found; however Brillard & Antoine (1990) is
more lenient requiring less outer perivitelline layer (OPVL) sperm/mm2 to pronounce an egg
fertile. Improved fertility predictions could have been made by using examination of inner
perivitelline layer (IVPL).
There was a tendency for a superior response in predicted fertility from birds with a protein
intake of 14.2 g CP/bird/day. This intake also least affected the BW of the male birds and thus
14.2 g CP/bird/day can be recommended for optimal BB male performance.
Description
Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.
Keywords
Poultry--Breeding., Poultry--Reproduction., Broilers (Chickens)--Breeding., Broilers (Chickens)--Reproduction., Poultry--Feeding and feeds., Poultry--Nutrition., Broilers (Chickens)--Feeding and feeds., Broilers (Chickens)--Nutrition., Proteins in animal nutrition., Theses--Animal and poultry science.