Effects of dietary algal docosahexaenoic acid oil supplementation on fatty acid deposition and gene expression in laying Leghorn hens

Abstract

SU MMARYThe purpose of the current study was to determine the effects of dietary docosahexaenoic acid (DHA) on fatty acid deposition in egg yolk and various tissues of laying Leghorn hens, and on the expression of hepatic lipogenesis-related transcription factors. There were three treatments with 10 Leghorn hens per treatment. Diets were based on maize-soybean meal (ME : 12 MJ/kg; CP : 171 g/kg ; Ca: 34 g/kg) supplemented with 0 (plus 20 g butter/kg), 5 g (plus 15 g butter/kg) or 20 g algal DHA oil/kg. The egg production of the birds was not affected by dietary DHA oil (P>0 . 05). The DHA content in egg yolks of the laying hens increased significantly (P<0 . 01) with the dietary supplementation of DHA. The DHA content of the total fatty acids in the egg yolk of laying hens was 4¡16, 11¡43 and 20¡90 g/kg for 0, 5 and 20 g/kg DHA treatments, respectively for the first week, and 6¡16, 18¡49 and 31¡86 g/kg for the second week. Therefore, algal DHA oil can be utilized by laying Leghorn hens to enhance egg yolk DHA content and produce high DHA eggs. The concentrations of triacylglycerol (TG) and cholesterol in plasma of laying Leghorn hens were not affected by dietary DHA treatments (P>0 . 005). The DHA content in plasma and livers of laying hens was increased with the addition of DHA in the diet (P<0 . 05). The DHA content in the skeletal muscle of Leghorn hens was also increased with the increase in dietary DHA. The data indicate that dietary DHA oil can be incorporated into plasma, egg yolks and various tissues. The mRNA concentrations of the lipogenesis-related transcription factors, sterol regulatory element binding protein 1 (SREBP1) and SREBP2, in the livers of laying Leghorn hens were not affected by the supplement of algal DHA oil for 2 weeks, suggesting that the expressions of these transcription factors are tightly controlled and not sensitive to DHA treatments in laying hens.

Blood Lipid Components and SREBP-1 Gene Expression in Broiler Chickens Fed Different Dietary Lipid Sources

“…Interestingly, in laying hens, dietary DHA as DHA oil was not effective on the expression of SREBP-1 gene in liver [7,9]. It has been speculated that in the laying hens, the de novo lipogenesis in the liver is genetically high in order to generate yolk [7].…”

“…Reverse Transcription (RT) PCR was carried out using RT-PCR kit 7 containing RNA (5 µg), 1200 nM of gene specific primer and 2 µL diethylpyrocarbonate-treated water. The mixture was incubated at 65 ˚C for 5 min, then 2 µL buffer RT enzyme, 1 µl deoxy nucleoside triphosphate mix, and 400 U/µL of MMuLV Reverse Transcriptase 6 were added to the above mixture.…”

The effect of feed supplementation with dietary sources of n‐3 polyunsaturated fatty acids, flaxseed and algae Schizochytrium sp., on their incorporation into lipid fractions of Japanese quail eggs

“…Diet supplementation of laying hens with different microalgae in order to increase DHA content in hen eggs has been successfully applied by many researchers (Cheng et al, 2004;Cachaldora et al, 2005;Rizzi et al, 2009). The fatty acid composition of the oil from Schizochytrium sp., apart from DHA, contains relatively high amount of DPA (16.32%, Table 1).…”

Influence of feeding stearidonic acid (18:4n-3)-enriched soybean oil, as compared to conventional soybean oil, on tissue deposition of very long-chain omega-3 fatty acids in meat-type chickens

“…Unfortunately, no significant effects due to dietary treatments were observed (Table 9), so this was not pursued. Others have also failed to observe any significant effects of dietary ALA on mRNA expression in chicken breast muscle elongases and desaturases in broilers (Haug et al, 2014) or of dietary DHA on mRNA concentrations of the lipogenesis-related transcription factors SREBP1 and SREBP2 in the livers of laying hens (Cheng et al, 2004). Haug et al (2014) concluded that the concentration of VLC n-3 PUFAs may be regulated independently of changes in the expression of elongases and desaturases, and possibly more by substrate competition.…”