Carotenoid intake and SCD genotype exert complementary effects over fat content and fatty acid composition in Duroc pigs1

Abstract

Nutritional and genetic strategies are needed to enhance intramuscular fat (IMF) and MUFA content without altering carcass leanness. Dietary vitamin A restriction has been suggested to specifically promote IMF, whereas a polymorphism of the () gene has shown to specifically increase MUFA. The purpose of this study was to investigate the combined effects of provitamin A (PVA) carotenoid intake and genotype (>) on hepatic retinoid content and on the liver, muscle (LM and gluteus medius [GM]), and subcutaneous fat (SF) content and fatty acid composition. Following a split-plot design, 32 castrated Duroc pigs, half of each of the 2 homozygous genotypes (CC and TT), were subjected from 165 to 195 d of age to 2 finishing diets differing in the PVA carotenoid content (an enriched-carotene diet [C+] and a control diet [C-]). Both diets were identical except for the corn line used in the feed. The C+ was formulated with 20% of a carotenoid-fortified corn (M37W-Ph3) whereas the C- instead used 20% of its near isogenic M37W line, which did not contain PVA carotenoids. No vitamin A was added to the diets. The C- was estimated to provide, at most, 1,300 IU of vitamin A/kg and the C+ to supply an extra amount of at least 800 IU vitamin A/kg. Compared with the pigs fed the C-, pigs fed with C+ had 3-fold more retinoic acid ( < 0.01) and 4-fold more gene expression in the liver ( = 0.06). The diet did not affect performance traits and backfat thickness, but pigs fed the C+ had less fat (4.0 vs. 5.0%; = 0.07) and MUFA (18.3 vs. 22.5%; = 0.01) in the liver, less IMF (5.4 vs. 8.3%; = 0.04) in the GM, and more fat content (90.4 vs. 87.9%; = 0.09) and MUFA (48.0 vs. 46.6%; = 0.04) in SF. The TT genotype at the gene increased MUFA ( < 0.05) in all tissues (21.4 vs. 19.5% in the liver, 55.0 vs. 53.1% in the LM, 53.9 vs. 51.7% in the GM, and 48.0 vs. 46.7% in SF for TT and CC genotypes, respectively). Liver fat and MUFA content nonlinearly declined with liver all- retinoic acid, indicating a saturation point at relatively low all- retinoic acid content. The results obtained provide evidence for a complementary role between dietary PVA and genotype, in the sense that the TT pigs fed with a low-PVA diet are expected to show higher and more monounsaturated IMF without increasing total fat content.

Transcriptome shifts triggered by vitamin A and SCD genotype interaction in Duroc pigs

“…In the present study, carcasses from pigs fed the VA-diet were 3.8 kg heavier than those fed the VA+ diet. Despite of this, dietary vitamin A had no effect on carcass lean content, which agreed with previous studies in different pig lines fed with restricted or elevated vitamin A [5][6][7][8][9][10][11].…”

“…The IMF of pigs fed a control feed (7500 IU vitamin A /kg) did not differ from pigs supplemented with > 10 times more vitamin A (100,000 IU/kg) [5]. Other authors have reported increases in IMF content with diets restricted in vitamin A [6][7][8][9][10], although the magnitude (and even the direction) of this effect depends on the genetic type of the pigs [11]. In contrast, the effect of vitamin A on IMF fatty acid (FA) composition is more robust across experiments.…”

“…The effect of dietary vitamin A on IMF deposition is particularly controversial in pigs. Several authors reported that a dietary reduction of vitamin A impacted the IMF content in m. gluteus medius [8], m. longissimus thoracis [9,11] and m. semimembranosus [7] in pigs of different genetic lines, although the direction and magnitude of the changes were very variable. For instance, Olivares et al [11] investigated the effect of supplementing the feed for 11 weeks with 100-fold the vitamin A daily recommendations of the National Research Council.…”

Modulatory Effect of Protein and Carotene Dietary Levels on Pig gut Microbiota

“…Feces samples were collected from 32 barrows of a pure Duroc line produced by 23 dams and 7 sires. A detailed description of the management and feeding conditions of these pigs during the experiment have been previously reported 22 . Briefly, all pigs were born within the range of 4 days (d) and castrated within the first week of age.…”

“…Modified crops such as high-carotenoid corn can impact directly in the levels of vitamins A in the feed 21 . In a previous work we have shown the combinatory effect of dietary protein and vitamin A on intramuscular fat content and composition 22 . In the present study we question whether pig microbiota diversity has been affected by these dietary interventions and can relate to some of the phenotypic changes.…”