Hemp seed oil and evening primrose oil were incorporated into the diets of laying hens for 5 weeks and the level of gamma fatty acid in the eggs that the treated hens laid was then evaluated. Hens were fed corn-soybean based diets that contained 5% tallow, 5% corn oil (CO), 5% hemp seed oil (HSO), or 5% evening primrose oil (EPO). The hemp seed oil and evening primrose oil influenced the amount of gamma linolenic acid found in the eggs through blood. The level of gamma linolenic acid in the plasma was significantly higher in hens that received the HSO and EPO diets than in those that received the tallow and CO diets. The HSO and EPO diets led to a 1.09% and 4.87% increase in egg gamma linolenic acids, respectively, when compared with eggs produced by hens treated with tallow and CO. Taken together, these data demonstrate that healthy eggs with increased gamma linolenic acids can be generated by minor diet modifications when hemp seed oil or evening primrose oil is included in the hen diet.

This study report that the gamma linolenic acid content of pork is higher in finishing pigs fed diets containing hemp seed oil, evening primrose oil or borage oil as the sources of gamma linolenic acid. Thirty six three crossing swines (Landrace×Yorkshire×Duroc), 80 kg of body weight, were randomly separated into four treatment groups with three pens per treatment and three animals per pen. The finishing swines were fed the experimental diets for 35 days until they reached the market weight of 110 kg. The animals were assigned to the four experimental diets: control diet containing 5.00% tallow, T1 containing 5.00% hemp seed oil(hemp seed oil 40 : soybean oil 60), T2 containing 5.00% evening primrose oil(primrose oil 40 : soybean oil 60), T3 containing 5.00% borage oil(borage oil 40 : soybean oil 60). The plasma triacylglycerol and total cholesterol content of the swine in the gamma fatty acids-fed groups were significantly(p<0.05) lower than those in the control group. No gamma linolenic acid was detected in the plasma of the control group, while the level of gamma linolenic acid treatment groups was significantly(p<0.05) higher than the control in the order of T3, T2 and T1. Moreover, the level of gamma linolenic acid increased with increasing number of feeding days. There was a significant difference between the treatment groups (p<0.05). There was a difference in the amount of saturated fatty acid and polyunsaturated fatty acid accumulated in the pork according to the treatment groups or the parts of the pork meat. The level of n-3 fatty acid of pork was highest in T1, which had been fed the hemp seed oil, followed in order by T3 and T2(p<0.05). The content of gamma linolenic acid in pork was highest in T3, which had been fed the borage oil, followed in order by T2 and T1(p<0.05). In particular, the level of gamma linolenic acid in pork increased in the order of the back fat, pork belly, ham and loin.

The objective of this study was to determine the effect of dietary oils on the levels of the γ-linolenic acid in chicken meat lipids. Three hundred ten five, 1-d old, male, Ross strain, broiler chicks were fed for 35 d to compare diets containing evening primrose oil(EPO) and hemp seed oil(HO) to a control diet. Fatty acid composition of lipid from chicken skin, thigh and breast muscle were determined at the end of the trial. The level of γ-linolenic acid of lipids from chicken meat fed diets containing EPO or HO was significantly higher than that of the control group(p〈0.05). The level of γ-linolenic acid of lipids from chicken skin was highest in the group, which had been fed the EPO 0.85%, followed in order by EPO 0.7%, 0.5%, EPO mixed oil, HO and HO mixed oil. There was a significant difference in the level of γ-linolenic acid of chicken skin between the control and treatment groups(p〈0.05). The level of γ-linolenic acid of lipids from chicken thigh muscle was also similar to skin, and significantly higher than that of the control group(p〈0.05). The level of γ-linolenic acid of lipids from chicken breast muscle was highest in the group, which had been fed the EPO 0.5%, followed in order by EPO 0.7%, 0.85%, HO 0.5% and HO mixed oil. There was a significant difference in the level of γ-linolenic acid of chicken breast muscle between the control and treatment groups(p〈0.05).