Abstract
The aim of this study was to evaluate the effect of the level of fat and selected fatty acids found in the milk of sows on the rearing of native breed piglets. Simultaneously, in order to improve the accuracy of the performed analyses, atomic absorption spectrometry was employed in the applied analytic methodology. The experimental animal material comprised 60 sows of the indigenous White Złotnicka breed. Colostrum and milk were collected on the first and 14th days of lactation. In all, 240 samples were collected. The following parameters were determined in the course of the experiment: number and weight of piglets, body weight gains as well as deaths of piglets. A total of 1270 born piglets was subjected to investigations. The performed experiments demonstrated that, with the progress of the lactation period, the content of fat and saturated fatty acids (SFA) turned out to be statistically significant and showed a growing tendency. Fat increased by about 2% and palmitic acid (C16:0) increased most, that is by 5%. Linolic (C18:2) and linolenic (C18:3) acids revealed decreasing trends. Irrespective of the day of lactation, the level of unsaturated fatty acids (UFA) determined in sows' colostrum and milk was higher in comparison with that of SFA, and the UFA to SFA ratio ranged from 1.84% to 1.33%. Proportions of n-6 to n-3 fatty acids were determined at the level of about 1.6:1.0 in the colostrum and 1.3:10 in milk. The highest daily body weight gains were recorded in the case of piglets derived from sows with the highest fat level - 294 g, while in the case of stearic acid (C18:0), the smaller its concentration in the colostrum and milk of the experimental sows, the better body weight gains of piglets - 262 g. At the same time, stearic acid (C18:0) was found to exert a statistically significant effect on piglet mortality at the level of P ≤ 0.05. Its highest concentration caused the highest proportion of deaths among piglets - 16.23%. The performed analysis of correlations that occurred between fat, fatty acids and traits associated with piglet rearing confirmed that linolic acid (C18:2; n-6) was highly significantly correlated with piglets' body weights (r = 0.456**) and was negatively correlated with piglets' deaths (r = -0.312). On the other hand, fat revealed correlation with body weight gains of piglets (r = 0.333*_ and a negative correlation with deaths of piglets (r = -0344*). Recapitulating, the results of the performed experiments revealed that differences in the levels of fat and fatty acids found in sows' colostrum and milk influenced results of piglet rearing. Together with the increase in the content of fat and UFA in sows' colostrum and milk, piglets were characterized by the best body weight, growth rate, as well as by small mortality.