Influence of feeding a milk replacer deficient in (alpha)-linolenic acid on fatty acid composition of various tissues in goat kids

Goat kids were fed for 5 weeks milk replacers with or without (alpha)-linolenic acid (C18:3n-3, ALA) and growth performance, plasma lipids and fatty acid composition of red blood cells, adipose tissue, liver, kidney, lymph node and spleen were examined. Ten animals were either given a milk replacer with 1.3% (% of total fatty acids) linoleic acid (C18:2n-6, LA) and 0.6% ALA or a milk replacer (ALA-free) with 1.2% LA and no ALA. The diets did not contain eicosapentaenoic (C20:5n-3) or docosahexaenoic acid (C22:6n-3). Both experimental milk replacers contained 224 g crude protein and 17 MJ metabolizable energy per kg air-dry matter. Crude fat contents were 131 and 124 g/kg air-dry matter in the control and ALA-free milk replacer, respectively. Growth performance of the goat kids was not affected by dietary treatment. The ALAfree milk replacer decreased the concentrations of plasma total and LDL cholesterol. After feeding the ALA-free diet, ALA was not detectable in any of the tissues and the erythrocytes. Except for adipose tissue and red blood cells, there was still eicosapentaenoic acid in the tissues of the goat kids fed the diet deficient in ALA, but the levels were markedly reduced. The present study shows that dietary ALA is not essential for growth in goat kids for a period of up to 5 weeks after birth. It is suggested that at birth the goat kids had sufficiently large stores of n-3 polyunsaturated fatty acids to prevent deficiency when fed the ALA-free milk replacer.