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The objective of the experiment was evaluation of some physical traits of egg quality in hens originating from Polish egg-type pedigree farms and destined for small-scale farming as well as in a breed of preserved chickens. 30 eggs from each of the three genetic groups (parental P55 Barred Rock strain, VH43 parental cross of V44 Rhode Island Red and H33 Leghorn strains, and the preserved Z11 Partridge Greenleg strain) were taken to analysis. The layers were maintained in the same environmental conditions and were under the same feeding regime.Analyses of egg quality were accomplished in 26th and 50th weeks of age, with an electronic EQM device. Egg weight in VH43 cross in the beginning of laying was 61.5 g and it was significantly bigger than in P55 hens (50.2 g) and Z11 hens (42 g). No statistical differences between experimental groups were found in shell thickness, shell density. Egg shell colour in P55 hens differed significantly from that in the other groups. The highest Haugh unit score (99.9) and albumen height (9.7 mm) were noted in the eggs of P55 hens in 26th weeks of age. These parameters lowered with age in all experimental groups. The highest proportion of yolk was found in the eggs of Z11 (29.5%) in 50 weeks of age. Yolk percentage increased with age in all genetic groups. Yolk colour index (La Roche) diminished with age of layers.
Climate variability greatly affects animals through direct and indirect effects. Animals with slow reproductive adaptation to ecological changes such as large mammals are likely to have evolved mechanisms to anticipate early such impacts of climate variability on the environment. One of the adaptive mechanisms between reproductive costs and benefits in mammals affects parental investment through biases in sex ratio. Deer might be likely to show an early detection of climate variability because conception takes place in early autumn, but the main raising cost in deer concerns lactation, which takes place at the end of the following spring. The aim of this paper is to assess whether there is a relationship between global indices of climate variability such as El Niño-Southern Oscillation (ENSO) and sex ratio of a captive population of deer. Results showed that there was a negative correlation (r=−0.65) between sex ratio and ENSO indices between 1996 and 2008. El Niño enhances drier conditions during the summer in the Iberia Peninsula, which in turn favours a female bias. Results also suggest that the mechanism of early detection of climate variability exerts a strong effect on female reproductive physiology because the long-term stability of food resources in our setting has not markedly reduced it.
The study was aimed at determining effects of feed ration on growth, within-group variability, and chemical composition of the body of juvenile zander (c. 25 g initial individual weight) grown out in a recirculation system for 42 days. The fish were fed a commercial pelleted trout feed offered at three rations (Group L: 1.2% of stock biomass; Group M: 1.6% of stock biomass; and Group H: 2.0% of stock biomass). Each experimental treatment involved two replicates. The feed rations used were found to significantly (p < 0.01) affect fish growth: the mean body weight on termination of the experiment was 47.9, 60.3, and 69.4 g in Group L, M, and H, respectively. Statistically significant differences were revealed also in SGR and fish condition. The most favourable food conversion ratio (FCR) and protein efficiency ratio (PER) were found in Group M, the between-group differences being significant as well (p < 0.05).
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