Impact of supplementation of various selenium forms in goats on quality and composition of milk, cheese and yoghurt.

摘要

The objective of this experiment was to monitor the possibility of influencing the composition of milk and milk products by supplementing the feed of lactating goats with selenium in various forms (natrium selenite and selenium proteinate). The trial was carried out in 30 goats, divided into 3 groups: Group C (n=10) was a control group, SeI group (n=10) received selenium in the form of natrium selenite and SeO group (n=10) in the form of lactate-protein complex produced by Lactobacillus acidophilus. Diverse selenium supplementations were carried out from 3.5-4.0 months before the date of delivery until the second month of lactation. In the time span of 2 weeks, milk from individual goats was taken six times and cheeses and yoghurts were made from the mixed milk from individual groups. During the period of milking and making milk products, the goats in experimental groups received added 565 micro g Se per animal per day in relevant forms. Long-term selenium supplementation in the form of natrium selenite/proteinate had no significant effect on the Se concentration in milk. Se concentration in milk of individual groups was as follows: C: 13.14+or-4.21 micro g/litre, SeI: 12.50+or-5.59 micro g/litre, SeO: 12.47+or-3.71 micro g/litre. Similarly, no significant differences in the selenium concentration were determined in yoghurts (C: 17.13+or-5.40 micro g/kg, SeI: 18.12+or-5.49 micro g/kg, SeO: 19.69+or-6.48 micro g/kg) and cheeses (C: 68.79+or-7.14 micro g/kg, SeI: 70.41+or-6.22 micro g/kg, SeO: 69.66+or-12.68 micro g/kg) made from milk of individual goats groups. Apart from selenium concentration in milk and milk products, we also monitored other quality indicators that might have been influenced by selenium supplementation in the goats' feed. Among qualitative milk indicators, we found significantly lower titration acidity and significantly higher rennetability in SeI group. We also determined a significantly higher fat concentration in milk of SeO group compared to the other two groups. Indicators monitored during production of yoghurts and cheeses were not influenced significantly, only fat concentration in yoghurts was higher in SeO group compared to SeI group. Supplementation of selenium in the form of natrium selenite and selenium proteinate exceeding the physiological needs of goats had no significant effect on the Se concentration in milk and milk products.