Nutrition markedly affects sheep milk composition and can be used to improve its suitability as food for humans. The effect of nutrition on sheep milk fat quality has been covered by many reviews. In contrast, nutrition and genetics interact on sheep milk protein. Milk true protein, whose mammary synthesis is under high genetic control, is much less affected than milk fat by nutritional management of the animals, whereas the non-protein nitrogen fraction of milk is largely affected by nutritional factors. Indeed, dietary-protein solubility and degradability and energy availability at rumen level can largely affect this fraction, especially milk urea. The latter is an excellent predictor of the protein nutritional status of sheep, based on the extent of nitrogen excretions through urine. Milk urea concentration is also an indicator of protein excesses and shortages associated with negative effects on the health, reproductive performance and immunocompetence of dairy ewes. Interestingly, milk urea concentration is inversely associated with somatic cell count (SCC) in sheep and cows. Nutritional errors can predispose the mammary gland to inflammations and, therefore, to a higher probability of mastitis occurrence, with a consequent increase in SCC in sheep milk. Moreover, specific dietary deficiencies in minerals (e.g. Se, Zn, Mn, and Fe) and vitamins (e.g. vitamin A, beta-carotene, and vitamin C) have also been associated with the health status of the mammary gland and SCC in milk. Recently, beneficial effects of dietary essential oils on SCC of sheep milk have been suggested. The nutrition as source of toxicants that could be transferred in sheep milk, will be updated and discussed. In conclusion, this review highlights that appropriate nutritional management can improve the composition of sheep milk, especially FA profile, and, to a certain extent, some milk compounds can be used to monitor the nutritional balance and health status of the animals.
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|Titolo:||Effects of nutrition on main components of sheep milk|
|Data di pubblicazione:||2020|
|Appare nelle tipologie:||1.1 Articolo in rivista|