Dietary Supplementation With DHA-Enriched Microalgae Powder To Improve Semen Quality Of Boars

In this experiment, boar diets were supplemented DHA-enriched microalgae powder in different proportions to study the effect of DHA-rich diets on semen quality, sperm fatty acid composition, and susceptibility to peroxidation. These researches are expeted to give more academic surports for improving the quality of boar semen.40 Duroc boars, aged 18-24 month-old, were selected to divided into five treatment groups, each 8 replicates, each replicate 1 boar. Corn, soybean meal and full-fat soybean form experimental diets, addition of microalgae powder were 0%,1%,2%,4% and 6%. Experimental lasted 10 weeks, boars were collected at a regular frequency(third times per two week), daily feed intake was 2.5kg. Semen were collected at week0, week8 and week10. Semen was centrifuged at 2600rpm for 20min at 4℃, the sample of seminal plasma were collected, the spermatozoa were re-suspended in the same volume of 9g NaCl L-1 and re- centrifuged. This process was repeated twice, spermatozoa were prepared. Spermatozoa were analysed for fatty acids composition. Seminal plasma and spermatozoa were analysed for SOD and MDA analysis. Blood were collected at week0, week8 and week10 by jugular venipuncture, centrifuged, the sample of blood serum were collected, for SOD and MDA analysis. Semen were collected at week0, week6, week8 and weeklO for semen quality evaluation, such as sperm volume, concentration, motility and abnormal sperm rate. Calculate total available sperm per ejaculate during weel 0,6,8 and 10; total available sperm per ejaculate during weeks 8-10. The details were as follows:(1) There is no significant effect on spermatozoa fatty acid composition before week 10(P>0.05). After 10 weeks, spermatozoa DHA and n-3 PUFA were significantly increased(P<0.01). Spermatozoa n-6 PUFA content were significantly decreased(P< 0.05). The adding level of 6% microalgae powder was significantly higher than 1% microalgae powder groups (P<0.05).(2) There is no significant effect on oxidative stress of boars received the diets supplemented DHA-rich microalgae powder(P>0.05). SOD activity in serum, seminal plasma and spermatozoa have no difference between the experimental groups was not significant (P> 0.05). MDA content in serum and spermatozoa have no difference between the experimental groups was not significant (P> 0.05)(3)There is no significant effect on sperm volume, concentration, motility and abnormal sperm rate of boars received the diets supplemented DHA-enriched microalgae powder(P>0.05). The diet contain 6% DHA-enriched microalgae powder after 10 weeks has a tendency to improve abnormal sperm rate(P=0.1116).These date suggested that:Supplementation of DHA-enriched microalgae powder to boar diets can change the fatty acid composition of sperm, increased DHA and n-3 polyunsaturated fatty acids, so increase membrane fluidity. At the same time, it can cause lipid peroxidation. Providing 300mg/kg VE to diet can effectively scavenge oxygen free radicals, alleviate oxidative stress. Although the improve on semen quality is not statistically significant. Supplementation with DHA-enriched microalgae powder after 10weeks, sperm per ejaculate increased and it should take a longer time to confirm the result.