USE OF HIGH LEVEL (4%) DIETARY GRAPE MEAL IN LAYING HENS DIETS

Margareta Olteanu, Tatiana Dumitra Panaite, Mariana Ropota, Monica Mitoi, Raluca Socoliuc, Rodica Diana Criste

Abstract
    The use in poultry diets of feed ingredients rich in polyunsaturated fatty acids requires the use of antioxidants to prevent fatty acids oxidation. The purpose of our experiment was to assess the use of a high level (4%) of dietary grape meal as antioxidant in layer diets rich in polyunsaturated fatty acids, on layer performance and egg quality. The 4-week trial used 99, Tetra layers aged 64 weeks assigned to three groups (C, E1 and E2). The basal diet (C) consisted of corn, sunflower meal and soybean meal. The experimental diets (E1 and E2) had additionally 7 % flax meal, while E2 included 4% grape meal as antioxidant. All diets had similar levels of protein and energy, 16.79 % CP and 15.13 MJ / kg gross energy. The diet formulations for the experimental groups had a higher level of α linolenic acid (omega-3) (13.96 g/100 g fat, in E1, and 15.13 g/100 g fat, in E2) than the formulation for group C, 1.25 g/100 g fat. The ratio of PUFA omega-6/omega-3 in the fat of the compound feeds for the experimental groups decreased by 93.34% for E1 and by 93.57% for E2, compared to group C. The grape meal, with 3.86 mg gallic acid equivalent/g as polyphenols content, and an antioxidant capacity of 34.99 mM Trolox equivalent/g, increased the antioxidant capacity in the methanolic extracts from the eggs harvested from the experimental groups: 96.72 mM Trolox equivalent /g yolk in E1, 100.10 mM Trolox equivalent /g yolk in E2, compared to 91.78 mM Trolox equivalent /g yolk in group C.

Key words: eggs; PUFA; antioxidants; grape meal