I . Groups of turkeys were given, to 10 weeks of age: diets E, basal, containing 2.3 yo mainly cereal lipid; A, basal plus 2.5 % beef fat; B, basal plus 2.5 % anchovy oil; C , as B, plus 0.02 % ethoxyquin; D, basal plus 5 % anchovy oil. Lipids from breast and leg muscle of all five groups were fractionated by thin-layer chromatography into five ' neutral' and six phospholipid fractions and the fatty-acid composition of each was determined by gas-liquid chromatography.2 . Individual lipid fractions differed widely in fatty-acid composition and in the degree to which they could be influenced by dietary fat supplements. Small but usually consistent differences were observed between corresponding fractions from breast and leg. Sphingomyelin (SP) and lysophosphatidylcholine contained largely saturated acids (76-80 76) ; the other phospholipids were 44-48 % and the 'neutral' lipids 38-50 % saturated. Phosphatidylserine (PS), phosphatidylinositol (PI) and, in less degree, phosphatidylethanolamine (PE) were rich in stearic acid, though palmitic was much more abundant in the diets and in the other muscle lipids. SP contained no acid more unsaturated than linoleic (1-2 %). PE and PI were richest in arachidonic and PE and PI in other polyene acids.3. The effects of beef fat on the muscle lipids were small and mainly on the 'neutral' fractions.4. The polyunsaturated fatty acids of the fish oil extensively displaced linoleic (and oleic) acids from all fractions (except SP); arachidonic acid was displaced from PE but not from PI.5. The degree to which the fish-oil polyunsaturated acids of the three series entered the muscle lipids varied with the acid and with the fraction. Docosahexaenoic acid (22: 6) reached a concentration of 20-25 % in PE, nearly five times as great as its concentration in the dietary lipid.6. Hydrolysis with phospholipase A showed that most of the unsaturated fatty acids were present in the 2-position of PC and PE, but the positional specificity was not complete, particularly for the less highly unsaturated acids.7. The antioxidant ethoxyquin had no effect on the fatty-acid composition of any of the muscle lipid fractions.

1. Lipid extracted from breast and leg muscle of 10-week-old turkeys was fractionated by preparative thin-layer chromatography and five individual ‘neutral’ and eight individual phospholipid fractions, representing 95% by weight of the extractable lipid, were recovered from the plates for analysis.The ‘neutral’ lipids from breast and leg muscle consisted mainly of triglyceride (202–497 and 1644–2333 mg/100 g), together with cholesterol (74 and 103 mg/100 g), free fatty acid (27 and 123 mg/100 g), diglyceride (17 and 66 mg/100 g) and cholesterol ester (9 and 12 mg/100 g).The phospholipids contained phosphatidylcholine (367 and 500 mg/100 g), phosphatidylethanolamine (157 and 279 mg/100 g), phosphatidylinositol (60 and 109 mg/100 g), sphingomyelin (43 and 62 mg/100 g), phosphatidylserine (31 and 61 mg/100 g), ‘cardiolipin’ (23 and 35 mg/100 g), lysophosphatidylcholine (9 and 11 mg/100 g) and ‘origin fraction’ (6 and 7 mg/100 g), accounting together (700 mg and 1070 mg/100 g for breast and leg muscle respectively) for 98% of the lipid phosphorus extracted.Partial replacement of carbohydrate in the cereal-based diet by beef fat (2·5%) or anchovy oil (2·5 or 5·0%) had no effect on the amount of any of the lipid fractions, except for triglyceride, which varied considerably and was lowest in tissue from groups receiving 2·5% anchovy oil.

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.

I. Digestibility of niaize stalk from lroyer Reid (Tr) maize and its isogenic mutant (bml) was studied by suspending nylon bags containing ground tissue in the rumen of a fistulated steer. The animal was given a grass hay-conccntrate ( 5 : 3) diet or a maize silage-grass hayconcentrate (4: I : 3) diet.2. The digestibility of the organic matter of the mutant maize stalk was greater than that ofthe normal maize stalk.3. Adaptation of the rumen to maize silage increased the organic-matter digestibility of the maize stalk.4. Lignin content was determined by two methods, namely organic matter insoluble in 72 "/, sulphuric acid (method of the Association of Oficial Agricultural Chemists, 1960) (AOAC-lignin) and the organic matter lost from the ligno-cellulose complex (rcprescnted by acid-detergent fibre) by oxidation with potassium permanganate. The AOAC-lignin concentration was twice the pcrmanganatc-lignin concentration, but the amount of ligninestimated by both methods showed a significant negative relation to organic-matter digestibility. The AOAC-lignin concentration was greater in Tr than in bm, maize but the permanganate-lignin concentration in Tr was slightly lower than in bm,. .There was an irregular relationship between the amount of lignin extractable with dimethylformamide (DNIF) and digestibility of organic matter due to the solution of some of the DMF-lignin during digestion. The loss of lignin was greater from the mutant maize stalk tissue than from the parent maize stalk tissue.6. The chemical composition of DMF-lignin determined by analysis showed a significant correlation between the syringealdehyde, p-hydroxybenzaldehyde and vanillin concentrations, and digestibility of organic matter. 7. Highcr concentrations of both phenolic aldehydes and acids wcrc found in the less digestible Tr material than in the bm, stalk tissue.Ruminants have a digestive system which enables them to utilize fibrous pIant material. However, the efficiency of utilization of the carbohydrate and protein constituents of the plant varies and is related to, among other things, the degree of lignification (Van Soest, 1967). The lowering of the digestibility of plant organic matter by lignin is believed to be caused by the physical inaccessibility of cellulose to the microbial enzymes due to lignin encrustation of the microfibrils (Sullivan, 1962), the inability of microbial enzymes to degrade the lignin polymer (Van Soest, 1966) and the inhibition of enzymes by phenolic constitucnts of lignin (Patton & Gieseker, T h e various studics which have been conducted to elucidate the relationship between lignin contcnt and forage digestibility have been reviewed by Ely, Kane, Jacobson & Moore (1953), Dehority, Johnson & Conrad (1962) Preparation of the maize stalk tissues. T h e bm, maize used in this study was introduced into the genotype of the inbred line TY by six generations of back-crosses. It is isogenic with the inbred Tr except for the bm, locus and possibly some adjacent loci. The two inbred lines were planted on 19 May 1...

No abstract