Effect of marine algae supplementation on the fatty acid profileof milk of dairy goats kept indoor and on pasture

Abstract

Nowadays, there has been increased interest in the modification of the fatty acid composition of milk and milk products by different feeding strategies. Composition of n-3 polyunsaturated fatty acids (PUFA) and rumenic acid (c9t11 C18:2) in milk, which could be improved by different way of feeding methods is the main concern. Increasing the supply of n-3 PUFA (such as grazing, oils, seeds or algae supplements) in the diet is one of the most essential ways of improving the bioactive composition of goat milk. Earlier reports showed that grazing considerably increased the rumenic acid and n-3 fatty acids contents in goat milk (Pajor et al., 2009; Delgadillo Puga et al., 2015). However, the most popular way to improve composition of foodstuffs by n-3 PUFA is supplementing animal diets with different plant oils, seeds, fish oil, freshwater and marine algae (Moate et al., 2013; Tsiplakou et al., 2017; Białek et al., 2018a). Moreover, fish oil and marine algae supplements in diets of ruminants are ABSTRACT. The aim of the study was to investigate the effect of the Schizochytrium limacinum marine algae on the fatty acid profile of goat milk, with particular reference to n-3 fatty acids, especially docosahexaenoic acid (DHA) and rumenic acid. Forty dairy goats were randomly allocated to four groups: C – fed with 1500 g alfalfa hay and 600 g concentrate; CMA – received the same forages and concentrate supplemented with 15 g/head/day microalgae; P – kept on pasture with 600 g concentrate; PMA – kept on pasture with 600 g concentrate with microalgae inclusion (15 g/head/day). The C and CMA groups were housed indoors, while the goats from P and PMA groups were kept on a natural pasture. The experiment lasted 31 days, including the last 10 days of sampling period. Marine algae feeding had no negative effect on milk yield and milk composition. The microalgae inclusion considerably increased DHA concentration in milk in both marine algae groups (0.40% in CMA and 0.39% in PMA), and additionally the n-6/n-3 ratio was also more favourable in the microalgae supplemented groups (1.25 and 1.37 in CMA and PMA groups, respectively) as compared to the C and P groups respectively in which this ratio was 2.30 and 1.44 (P < 0.01). Also, marine algae supplementation increased the concentration of rumenic acid (0.89% and 1.07% in CMA and PMA groups, respectively) in milk in comparison to C (0.46%) and P (0.77%) groups. So, it can be concluded that diet supplemented with microalgae significantly increased the concentration of beneficial fatty acids in goat milk. Received: 14 September 2018 Revised: 28 February 2019 Accepted: 18 June 2019