| Popis: |
The influence of photoinduction on egg quality traits and histodifferentiation of the magnum in 360, 20 weeks old pearl guinea fowl were investigated by exposing the birds to three photoregimen – Natural daylight (NDL); restricted to 8 hours of daylight per day for 8 weeks plus stimulatory light for 16 hours per day for 4 weeks (RSL); natural daylight for 8 weeks plus stimulatory light for 16 hours per day for 4 weeks (SL). Birds on the RSL treatment laid smaller (P>0.05) eggs than did the birds on NDL and SL probably on account of their earlier age at first egg. Shell weight in all the groups increased slightly (P>0.05) until 30-34 weeks of age and thereafter stayed constant throughout the laying period with its percentage relative to egg weight decreasing with advancing age. There were non-significant differences (P>0.05) in albumen height, yolk index, egg index and Haugh unit values. However, lower (P>0.05) average Haugh unit values during the laying cycle was recorded for the RSL birds when compared with the NDL and SL birds. Mean scores for histodifferentiation in the developing magnum as index of egg production and development in the female guinea fowl were highest in the RSL (8.22), followed by the SL (5.45) and NDL (3.45). This suggests that photoinduction helps advance the rate of maturation of the organ. Keywords: Photoinduction, egg quality, Histodifferentiation of the magnum, guinea fowl. [IJARD Vol.3 2002: 108-115] |
