RESUMO
Brown trout (Salmo trutta) broodstock from a single population were separated prior to spawning andexposed to two different holding environments: a raceway system and a tank system. Eggs were stripped from females and 13 measures of egg qualitywere collected, analysed individually, combined by principle components analysis into an integrated egg quality score which was validated against egg survival.The multivariate egg quality score (PC1) differed for fish held in the tank and raceway systems. Egg survival, chorion breaking strength and chorion Se concentrations were higher in eggs produced by broodstock held in the tank system compared to those in the raceway system. In contrast, chorion concentrations of P and K were higher in eggs from fish held in the raceway system. The results suggest that brown trout broodstock reared in tank systems produced higher quality eggs compared to trout reared in raceways. Finally, this study also indicates that multivariate statistical analysis can be used to determine egg quality from multiple egg parameters.(AU)
Assuntos
Animais , Salmonidae/anatomia & histologia , Salmonidae/embriologia , Salmonidae/fisiologia , PesqueirosRESUMO
Brown trout (Salmo trutta) broodstock from a single population were separated prior to spawning andexposed to two different holding environments: a raceway system and a tank system. Eggs were stripped from females and 13 measures of egg qualitywere collected, analysed individually, combined by principle components analysis into an integrated egg quality score which was validated against egg survival.The multivariate egg quality score (PC1) differed for fish held in the tank and raceway systems. Egg survival, chorion breaking strength and chorion Se concentrations were higher in eggs produced by broodstock held in the tank system compared to those in the raceway system. In contrast, chorion concentrations of P and K were higher in eggs from fish held in the raceway system. The results suggest that brown trout broodstock reared in tank systems produced higher quality eggs compared to trout reared in raceways. Finally, this study also indicates that multivariate statistical analysis can be used to determine egg quality from multiple egg parameters.
Assuntos
Animais , Salmonidae/anatomia & histologia , Salmonidae/embriologia , Salmonidae/fisiologia , PesqueirosRESUMO
An experiment was conducted to evaluate the effects on eggshell quality of supplementing the diet of laying hens with a combination of Zn, Mn, and Cu from organic or inorganic sources. Three groups of hens, aged 32, 60, and 69 wk were fed a corn-soybean basal diet containing 32.6 mg/kg Zn, 24.7 mg/kg Mn, and 4.95 mg/kg Cu or a basal diet supplemented with 30-30-5 and 60-60-10 mg/kg of Zn, Mn, and Cu, respectively. Addition of Zn, Mn, and Cu in combination increased their concentrations in egg yolk and slightly decreased egg weight during some sampling from aged hens. The Zn, Cu, and Mn dietary supplementation did not affect the following measures of eggshell quality: percentage eggshell, eggshell index (shell weight per unit surface area), and eggshell stiffness. However, there was a small increase in elastic modulus of the eggs from one group of the older hens due to supplementation with Zn, Mn, and Cu. More consistently we observed improved breaking strength and fracture toughness (resistance to fracture) in the two oldest groups of hens at 1, 5, and 9 wk after introduction of the experimental diets. The effect was observed regardless of the source of trace elements.