Ingrid Halle

Effect of soy oil supplementation and protein level in laying hen diets on praecaecal nutrient digestibility, performance, reproductive performance, fatty acid composition of yolk fat, and on other egg quality parameters

An experiment was carried out with laying hens in the age of 22—45 weeks to examine the effects of added soy oil (0%, 3.5%, 7%, 10.5%, and 14%) and dietary protein level (13.2% and 16.3%) on laying and reproductive performance, fatty acid composition of yolk fat, and other egg quality parameters. Moreover, digestibility of nutrients and of energy was determined by using a marker technique. Laying intensity and feed intake were not influenced by dietary treatments whereas egg weight and daily egg mass production were significantly improved by soy oil addition in a non-linear related manner. The feed conversion ratio reached a minimum at soy oil proportions between 3.5% and 10.5%. Reproductive performance in terms of fertilized eggs, hatchability, and mortality of chicks was not affected by dietary treatments. The increase of egg weights due to soy oil addition was accompanied by a simultaneous increase in the proportion of albumen and a decrease of yolk and shell percentage. Palmitic acid (C16:0) and oleic acid (C18:1) proportions in yolk fat decreased as soy oil addition was increased whereas the proportions of linoleic acid (C18:2 n-6), linolenic acid (C18:3 n-3), and docosahexaenoic acid (C22:6 n-3) were increased at the same time. Praecaecal digestibility of crude fat and fatty acids of the diets were non-linearly improved by soy oil addition. Digestibility of crude protein and amino acids were not affected by either protein content of the diet or by soy oil supplementation. In conclusion, a decrease in dietary protein content from 16.3% to 13.2% did not negatively influence performance of hens and egg quality under the experimental conditions applied. Soy oil addition improved egg quality.

Pre-hatching temperature training improves performance in dual- and laying-type cockerels fed with different protein and energy concentrations

The hypothesis of the present study was that pre-hatching temperature training (PTT) with short-term warm stimulation might improve hatching results and have long-lasting effect on growth performance, production efficiency, and robustness in laying-type and dual-purpose cockerels. Further, during the growth period these results may be modified by the protein and energy level of the diet. A total of 2880 eggs (Lohmann Brown-LB/Lohmann Dual-LD) were incubated from day 1 to 17 under normal incubation temperature (37.2–37.4°C) and until hatching in two groups with different temperature programs (control: 37.2–37.4°C or PTT: plus 1°C above standard for 2 h daily). For a subsequent 70 days growing period, 160 LB and 160 LD cockerels from each incubation group were randomly distributed in 8 treatments (8 pens/treatment; 10 birds/pen) resulting from two genotypes of cockerels, two incubation programs, and two dietary protein/energy levels (200 g crude protein/11 MJ AME N/kg – low level, LL; 215 g/12 MJ – high level, HL). PTT had no negative effect on hatching results in LB and LD cockerels. The origin of cockerels had a significant effect on feed intake, growth performance, and feed to gain ratio. The final body weight at day 70 was 85% higher in LD than in LB cockerels (2500 g/1351 g). In LD, but not so pronounced in LB cockerels, performance and production efficiency were significantly improved by PTT. In LD cockerels, the final body weight on day 70 reached in the LL and HL fed groups 2558 and 2528 g, respectively (control: LL 2432 g/HL 2482). Over the total growing period the feed to gain ratio was 10% higher in the LL fed LB/LD groups (2.56/2.29 kg/kg) compared with the HL groups (2.30/2.06 kg/kg). From day 1 until 49, the lowest feed to gain ratio ( P<0.05) of 1.81 kg/kg was calculated for the PTT group of LD cockerels fed with HL feed. Slaughter after 70 days showed significant differences in breast meat and legs, and percentage of abdominal fat between bird genotype and of the different incubated groups. While the thyroid weight was influenced by genotype only, the bursa weight depended also on experienced PTT at the age of 70 days. Possibly, robustness and therefore stress- and immune response might benefit from PTT in both LD and LB cockerels as indicated by increased mean relative bursa weight of 18 and 21%, respectively.