Effects of dietary fish oil on the composition and stability of turkey depot fat

Abstract

I . Beef fat (2.5 %) and anchovy oil (2.5 %; 2.5 yo plus 0.02 % ethoxyquin; 5 %) were incorporated into isocaloric cereal-based diets A, B, C and D and given to turkeys from z to 1 0 weeks of age. Diets A, B, and C contained 13 and diet D 26 i.u. a-tocopheryl acetate/kg. The lipids of diets B and D, which contained fish oil without ethoxyquin, autoxidized in the feeding troughs, but not seriously in the brief period of exposure permitted. 2. The birds all remained healthy and grew well, the only nutritional effects of the fish oil being a depressed storage of vitamin A in the liver at both levels of feeding (prevented by ethoxyquin) and a slightly adverse effect, at the higher level only, on food conversion ratio. 3. The skin fats of the birds given fish oil contained seven major and two minor fatty acids, derived from the fish oil, which were not present in the skin of the control group given beef fat, as well as one major fish oil acid present in much greater concentration in the birds given fish oil than in the controls.All these acids were present in the skin fats at about half or two-thirds of their concentrations in the dietary lipid, except for acid 2 2 : 5 , which reached two or three times this level. 4. The stabilities towards autoxidation of the skin fats decreased in the order A > C > B > D, as their content of polyunsaturated fatty acids increased, but the greater stability of group C as compared with B was probably due, in the main, to the higher tocopherol content of the skin fat of the birds on the ethoxyquin-containing diet. Fishy flavours which devcloped on cooking showed a similar relationship to diet.

Influence of Residual Lipids on Nutritive Value of Fish Meal

“…The correlation between the fatty acid composition of the carcass lipids and that of the dietary lipids found in this experiment is in agreement with previously reported findings (Neudoerffer & Lea, 1966, Miller et al, 1967, Opstvedt et al, 1970. The levels of the typical marine fatty acids in the carcass lipids in this experiments when 10% of fish lipids were fed, were however, higher than that found in a previous expcriment (Opstvedt ct al., 1970) in which the chickens received 24.4% fish meal equal to about 3% fish lipids.…”

“…The observations by Neudoerffer & Lea (1966) in turkeys show that the 20:5, 22:5 and 22:6 acids can replace linoleic acid in the phosholipid molecules, but they do not indicate any difference between these acids with regard to their incorporation into neutral fats. The reciprocal relationships between the tissue contents of 18:l and 18:2, on one hand, and the content of the polyenoic acids, on the other, agree with previous experiments (Neudoerffer & Lea, 1966;Miller et al, 1967;Opstvedt et al, 1970) and indicate that these fatty acids replace each other in the lipid molecules.…”

“…In feeding experiments it has been established that antioxidant stabilized fish meals have slightly higher energy values, but cause a greatsr incorporation of polyenoic fatty acids and increase the degree of fish taints in the meat ds compared with unstabilizcd fish meal (Opstvedt et al, 1970. Although studies on the metabolism of marine fatty acids have been reported (Neudoerffer & Lea, 1966), information on the quantitative aspects of the utilization of the fish meal lipids as affected by methods of processing and storagc are lacking. Since the fatty acid composition is important both for the flavour quality and for the nutritive value of the poultry meat, it is important to know how dietary intakes of fish lipids affect the fatty acid composition of the meat.…”

Stability of abdominal fat and meat of broilers: Relative effects of vitamin E, butylated hydroxytoluene and ethoxyquin1

“…Webb et al (1972a) observed that BHT at concentrations below 0-04% and EQ below 0'02% were ineffective in reducing rancidity, while 0-04% EQ gave some improvement. The latter markedly improved the stability of carcass fat in turkeys as well as the storage of vitamins A and E in their bodies (Neudoerffer and Lea, 1966). Cort (1974) reported that, compared with food-grade synthetic antioxidants, tocopherols have poor activity in vegetable oils, but are better in animal fat.…”

Occurrence of Waxes in Acinetobacter

“…(modified from Mangold, 1961); solvent B, petroleum ether +diethy1 ether, 9: I (by vol.). Either chromic acid (Rouser, Galli, Lieber, Blank & Privett, 1964) or fluorescent reagent (Neudoerffer & Lea, 1966) was used to detect lipids. Samples to be analysed by gas-liquid chromatography (GLC) were inter-esterified with sodium methylate (de Man, I 964) and resolved on columns containing polyethylene glycol adipate (PEGA) or methyl silicone gum E3o (E3o) according to the procedures of Neudoerffer & Lea (I 966).…”