Zoran Škrtić

The effect of different oil supplementations on laying performance and fatty acid composition of egg yolk

Abstract The aim of the research was to determine effects of different combinations of rapeseed and fish oil - instead of soybean oil - on the performance of laying hens and on the profile of fatty acids in egg yolks, especially on n-3 polyunsaturated fatty acid (PUFA), when such oils are added to the diet of laying hens. The research was carried out on 90 laying hens of the Hy-Line hybrid ranging in age from 32 to 36 weeks old. Hens were divided into three groups (30 laying hens per groups) and fed with a commercial mixture that contained 17% of crude protein and 11.6 MJ ME. The research lasted for 28 days. The control group (C) was given diets with soybean oil supplemented in the amount of 5%, and experimental groups (E1 and E2) were fed diets that contained a combination of fish and rapeseed oils in different amounts. Diets given to the E1 group contained 3.5% of fish oil and 1.5% of rapeseed oil, while the E2 group was fed diets with 1.5% of fish oil and 3.5% of rapeseed oil. Production characteristics of hens were monitored during the whole experiment. Portion of saturated (SFA) and unsaturated fatty acids (MUFA and PUFA), as well as α-linolenic (αLNA, C:18:3n-3) eicosapentaenoic (EPA, C20:5n-3) and docosahexaenoic (DHA, C22:6n-3) acid were shown as a percentage of total fatty acids contained in yolk. There were statistically significant differences (P<0.05) only in the hens’ end weights and laying intensity between the C and E1 group, as well as between the C and E2 group. The portion of SFA in total fatty acids contained in yolk was not statistically significant (P>0.05) among investigated groups. Higher content of MUFA was noticed in both experimental groups, if compared to the control (E1 41.37%: E2 40.72%, C 36.95%, P<0.05). Content of αLNA differed significantly (P<0.001) between E1 and the control group, and the content of DHA differed significantly (P<0.001) between E1 and the control group, as well as between E2 and the control group. Total n-3 PUFA was increased in the E1 group for 2.10, and in the E2 group for 1.41 times than in the control group. The ratio of n-6/n-3 PUFA was the lowest (P<0.05) in egg yolks of the E1 group (4.01), followed by that of the E2 group (6.56), and finally that of the control group (11.08).

Beneficial effects of different dietary oils on cholesterol level and fatty acids profile of turkey pectoral muscle

Abstract Human health depends to a great extent on the quality of consumed food. The relationship between the diet and health is increasingly evident. Therefore, the exact food composition, as well as the possibilities of its improvement, is intensively investigated. Turkey pectoral muscle is often recommended today as the most healthy meat product. The aim of our study was to improve the pectoral fat content of turkeys by adding some extra fat sources to their meals. The study was performed on 90 female turkeys of the hybrid Nicholas 700, in their final fattening period (from 15th to 19th week of age). Turkeys were divided into three groups, each represented by 30 individuals, and fed with meals differing in fat source, in the amount of 3% of the total meal weight. The added fat in the first group came from the commercial preparation Bergafat. Pronova Biocare Epax 3000 TG was added to the food of second group, while the third group had rapeseed oil added. After the fattening period, the quality of pectoral muscle was determined for the 10 carcasses from each experimental group (water holding capacity - WHC, meat color, protein, fat, ash, water, cholesterol and fatty acids content). Meat color did not differ between the investigated groups, while WHC statistically differed (P<0.05). Turkey muscles in the first group had the best WHC (7.76 cm2), while the the second group had the worst (9.12 cm2). No difference could be shown in the turkey muscle protein, water and ash content between the experimental groups. However, the second experimental group had a lower total lipid content (1.73%, P<0.05) compared to the first (1.97%) and third (1.93%). Turkeys from the first and second groups had lower cholesterol concentration in the pectoral muscle lipids (21.74 and 18.04 mg/100g, respectively, P<0.05) compared to the third group (41.00 mg/100g). The second experimental group had the highest PUFA content (P<0.001) and lowest n-6/n-3 ratio (P<0.001) compared to the other experimental groups. We concluded that the most favourable effects on the lipid status of turkey pectoral muscle was observed with the Pronova preparation, which lowered its total lipid and cholesterol concentration, raised PUFA content, and lowered the n-6/n-3 ratio. Further investigations, including combinations of added oils to the diet, should be directed to minimize the observed undesirable effects of Pronova preparation on turkey meat quality characteristics.

Market of poultry meat and consumers’ preferences in the Osijek-Baranja County

Abstract Poultry meat is the most consumed type of meat in Croatia. Yearly consumption of poultry meat amounts to 19.3 kg pro capite. Consumers prefer price-worthy and tasty meat, which is beneficial to their health. This research into the meat market and consumers’ preferences was based on a representative sample of 100 examinees, all residing in the region of Slavonia and Baranja. Among the poultry meat, the majority of examinees most often buy chicken meat (86%), and the rest of them prefer turkey meat (14%). Quality (65%) and price (30%) are the most important factors that influence consumers when buying poultry meat. Almost all consumers prefer to buy poultry meat in its main parts, mostly because of reasonable prices. Even 92% of them decide to buy the most valuable carcass parts (breasts, drumsticks and thighs). In the investigated area of the Osijek-Baranja County, poultry meat is consumed once a week by 86% of examinees.

The influence of different fat sources on fattening of turkeys and composition of fatty acids in breast muscles

Abstract The aim of this research was to evaluate the influence that different fat sources (Bergafat-BF, Pronova Biocare Epax 3000 TG-PBE and rape oil-RO) have on fattening characteristics of turkeys and composition of lipids in breast muscles, if added separately in the amount of 3% and also equally combined in finishing diets. The research was carried out on 180 heavy hybrid turkeys of Nicholas 700 provenience. Different sources of fat did not have statistically significant effect (P>0.05) on finishing weights, average daily weight gain, consumption and feed conversion. However, supplementation of the above stated fat sources changed highly significantly (P<0.001) the content of SFA, MUFA and EPA+DHA in the lipids of breast muscles. Rape oil, which was added to diets, had positive effect on the content of SFA and MUFA. In comparison to non-supplemented diets, supplementation of Pronova preparation to diets resulted in doubling of the desirable EPA+DHA.