Marija Starcevic

Effects of dietary selenium-yeast concentrations on growth performance and carcass composition of ducks

The aim of the present study was to assess effects of selenium (Se)-yeast diet supplementation on performance and carcass composition in ducks. The study was performed on 240 1-day old ducklings of the same origin (Cherry Valley hybrid), during a 49-day period, which were fed diets supplemented with the following four different levels of Se yeast (ALKOSEL® R397): groups with Se at 0 mg/kg of the diet as-fed, 0.2 mg/kg, 0.4 mg/kg and 0.6 mg/kg. Growth performance (bodyweight, daily weight gain, daily feed intake, feed-conversion ratio) and carcass characteristics (hot and cold carcass weight, chilling losses, dressing percentage, carcass cut yields, and percentage of tissues in breast and thighs with drumsticks) of the ducks were determined. Animals fed high-Se diets (0.4 mg/kg) had higher (P < 0.05) final bodyweight and daily weight gain (from 15 to 49 days) compared with those fed diets with inadequate (0 mg/kg) or with supranutritional (0.6 mg/kg) Se levels. Ducks fed only with basal diet showed a higher (P < 0.05) feed-conversion ratio (from 15 to 49 days) compared with those supplemented with Se at 0.4 mg/kg and 0.6 mg/kg. Dressing percentage was higher (P < 0.01) in the control group (69.50%) than in the group with Se added at 0.6 mg/kg (66.85%). The weights of basic cuts from the duck carcasses did not significantly differ among compared groups. Moreover, the percentage of skin with subcutaneous fat in breast and thighs with drumsticks increased in Se-supplemented groups compared with the control group, while the opposite was determined with the percentage of muscle. It was concluded that a diet containing 0.4 mg of added Se per kilogram produced the greatest growth-performance results in ducks.

Corrigendum to “The effects of dietary Selenium-yeast level on glutathione peroxidase activity, tissue Selenium content, growth performance, and carcass and meat quality of broilers”

Abstract The present study was conducted to assess effects of selenium (Se)‐yeast supplementation on glutathione peroxidase activity, Se levels in tissues, growth performance, carcass, and meat composition in broilers. A total of 275 one‐d‐old Cobb 500 broilers of both sexes were randomly allotted to 1 of 5 treatments during a 42‐d period. The 5 treatments differed only in Se content: group 1 had no additional Se (background only); groups 2, 3, and 4 received 0.3 mg/kg of added Se from the beginning of the trial until d 21, whereas in the second half of the study (from d 22 to 42), these groups received 0.3, 0.6, and 0.9 mg/kg of added Se, respectively; and group 5 received 0.9 mg/kg of Se for the entire experimental period. At the end of the study, the control group showed significantly lower (P < 0.01) glutathione peroxidase activity in blood plasma compared to Se‐supplemented groups. Regarding Se concentration in various tissues, the groups receiving Se yeast showed higher plasma, feces, and meat Se contents than the control group (P < 0.01). Supplementation of Se improved broilers’ body weight, weight gain and feed conversion ratio (P < 0.01). Dressing percentage was lower in the control group and the group with 0.3 mg/kg of added Se compared to other experimental groups (0.6 and 0.9 mg/kg of dietary Se). The proportion of less valuable carcass parts (wings and legs) was higher (P < 0.01) in the group fed the basal diet compared to groups supplemented with 0.9 mg/kg of Se. Initial and ultimate pH values differed among experimental groups (P < 0.05). Supplementation of Se improved the broilers antioxidative resistance, growth performance, carcass quality, and chemical composition of meat.

Survival of Salmonella spp. in minced meat packaged under vacuum and modified atmosphere

The effect of different modified atmosphere packaging regimes on the behavior of Salmonella spp. on minced meat was studied. Minced meat was experimentally contaminated with a Salmonella spp. cocktail (S. Enteritidis, S. Typhimurium, S. Infantis and S. Arizonae), packaged under vacuum or modified atmosphere with initial headspaces containing 20%O2/50%CO2/30%N2 and 20%O2/30%CO2/50%N2) and stored at 3 ± 1 °C for 12 days. Samples were analyzed for Salmonella spp., viable and lactic acid bacteria count every third day. Salmonella spp. counts decreased during storage in all packaging types, with reductions of about 1.5 log CFU/g. A significant difference (p < 0.01) was noted between Salmonella spp. counts in meat packaged in vacuum and modified atmospheres, although there was no significant difference in Salmonella spp. count between meat packaged in 50%CO2, and meat packaged in 30%CO2. At the end of the study, there were significant differences (p < 0.01; p < 0.05) in total viable and lactic acid bacterial counts between meat packaged in vacuum and modified atmosphere, and the lowest counts were noted in meat packaged in modified atmosphere with 50%CO2.