Egg quality traits of laying hens reared in organic and conventional systems

This study evaluated the effects of two dietary doses of vitamins E and C supplemented separately and together, on the content of vitamin E in the yolk, on the lipid stability of fresh and stored eggs, and on their sensory and functional properties. Hy-Line Brown hens (n = 216) received a basal diet for 8 wk supplemented with 100 or 200 mg DL-alpha-tocopheryl acetate (E100 or E200, respectively)/kg, 500 or 1,000 mg ascorbic acid (C500 and C1000, respectively)/kg, or 100 mg DL-alpha-tocopheryl acetate plus 500 mg ascorbic acid (E100+C500)/kg, whereas the control group received no supplementation. Fresh eggs and eggs stored 30,60, and 90 d at 4 C or stored 28 d at room temperature were analyzed for vitamin E content and TBA-reactive substances (TBARS). We also evaluated functional properties of fresh and cooked eggs and sensory properties of boiled and scrambled eggs. The yolk content of vitamin E depended on the level of dietary addition and decreased after 90 d of storage at 4 C or after 28 d at 25 C. Vitamin supplementation had no effect on fresh or refrigerated eggs, whereas 4 wk of storage at room temperature increased TBARS in the control and the group supplemented with the highest doses of vitamins. Ascorbic acid improved Haugh units and elasticity of albumen gels, whereas cohesiveness and hardness of yolk, albumen and whole-egg gels were not affected by dietary treatment. Panelists were not able to distinguish treated eggs from control eggs.

Temperature and time are two critical parameters in sous vide cooking which directly affect eating quality characteristics and food safety. This study aimed to evaluate physicochemical and microbiological properties of sous vide chicken breast fillets cooked at twelve different combinations of temperature (60, 70, and 80 °C) and time (60, 90, 120, and 150 min). The results showed that cooking temperature played a major role in the moisture content, cooking loss, pH, a* color value, shear force, and thiobarbituric acid reactive substances (TBARS). Increasing cooking temperature caused an increase in cooking loss, lipid oxidation, TBARS, and pH, while moisture content was reduced (p < 0.05). Cooking time played a minor role and only moisture content, cooking loss, and a* color value were affected by this parameter (p < 0.05). Total mesophilic aerobic bacteria, Psychrotrophic bacteria, and Enterobacteriaceae were not detected during 21 days of storage at 4 °C. Cooking at 60 °C for 60 min showed the optimum combination of temperature and time for sous vide cooked chicken breast fillets. The result of this study could be interesting for catering, restaurants, ready-to-eat industries, and homes to select the optimum combination of temperature and time for improving the eating quality characteristics and ensuring microbiological safety.

Lipid composition of covering and intramuscular fat in pigs at different slaughter age

This trial was carried out to compare the effect of the dietary supplementation of high doses of either synthetic pigment ethyl ester of β-apo-8′-carotenoic acid (apo-ester) or natural pigments, mainly lutein and zeaxanthin, extracted from Tagetes erecta, on egg quality of hens laying brown shell eggs (ISA Brown) and white shell eggs (Hy-Line White W-36). The hens of each strain were divided into 6 groups and fed a corn-soybean basal diet supplemented either with 40, 60, and 80 ppm of apo-ester (APO) or with 120, 180, and 240 ppm of marigold extract (MAR). Egg pigmentation rose linearly and significantly (P < 0.01) as the dietary levels of apo-ester increased, but this did not occur when MAR supplementation was used. The amount of β-carotene equivalents in whole liquid egg of MAR treatments was almost constant with varying pigment dietary dose and was significantly lower (P < 0.01) than in APO treatments. In both hen strains, whole liquid egg redness (a*) and yellowness (b*) were higher with APO supplementation. The egg component weights were highly affected (P < 0.01) by the hen strain, with yolk:egg ratio higher in the Hy-Line. The trial confirms that in spite of the higher level of MAR supplementation, APO has a better efficiency in whole liquid egg pigmentation. The ISA Brown hens showed a better ability to absorb dietary carotenoids than did the Hy-Line White.

The purpose of the research was to study the effects of high and low stocking density of broiler chickens, different types of litter and the adoption of short and long lighting regimen on broiler welfare through the evaluation of their productivity and incidence of foot pad dermatitis. 2,400 male Ross 508 were divided into 8 groups of four replicates each and reared in 32 pens according to a 3 factors experimental design of two levels each: low (LD) or high (HD) stocking density (11 and 14 birds/m2 for LD and HD respectively), chopped straw (CS) or wood shaving (WS) litters and short (SL) or long (LL) light regimens (16 h light and 8 h dark or 23 h light and 1 h dark respectively for SL and LL). Broiler growth rate and feed efficiency were positively influenced by a stocking density lower than 30 kg of live weight per m2. The adoption of a short light regimen reduced feed intake and improved feed conversion rate without modifying body live weight. Chickens reared on wood shaving litter showed a lower incidence of foot pad dermatitis.