Effects of Different Types of Dietary Fibers on Lipid Metabolism and Bile Acids in Weaned Piglets.

The aim of this study was to investigate the effects of dietary fiber on the serum biochemistry, bile acid profile, and gut microbiota in piglets. Twenty-four pigs (initial body weight: 10.53 ± 1.23 kg) were randomly divided into three treatments with eight replicate pens of one pig per pen for 21 d. The dietary treatments consisted of the following: (1) a fiber-free diet (NS); (2) a fiber-free diet + 3% fructooligosaccharides (SI); (3) a fiber-free diet + 3% dietary fiber mixture (fructooligosaccharides, long-chain inulin, and microcrystalline cellulose at the ratio 1:1:1; MIX). The results showed that compared with the NS group, the 3% SI diet reduced the serum total cholesterol (TC) concentration of the piglets (p < 0.05). The metabolomics results showed that the 3% SI diet increased the level of taurohyocholic acid (THCA) and α-muricholic acid, and the 3% MIX diet increased the level of THCA and cholic acid (p < 0.05). The use of 3% SI or MIX decreased the glycodeoxycholic acid (GDCA) level in the bile of the piglets (p < 0.05). The correlation analysis shows that the GDCA was positively related to the TC. The 16S rRNA gene sequencing results showed that UCG-002 and Holdemanella were enriched in the SI group, while Bacteroides was enriched in the MIX group. The microbial function prediction indicated that SI supplementation tended to elevate the relative abundance of gut bacteria capable of expressing bile acid-metabolizing enzymes. To sum up, the regulatory effect of dietary fiber on lipid metabolism is related to bile acids in piglets. Compared with MIX, SI is more likely to regulate bile acids through the gut microbiota.

Analysis of ethoxyquin and its oxidation products in swine tissues by gas chromatography-tandem mass spectrometry for evaluating the feed-to-animal tissue transfer of ethoxyquin and its metabolites.

BACKGROUND: Ethoxyquin (EQ) is a common antioxidant which is widely used in animal feed. But the supplement of EQ in animal feed may lead to the residues of EQ and its major oxidation products: ethoxyquin quinone imine (EQI) and ethoxyquin dimer (EQDM) in animal tissue. Thus, it would pose potential health hazards to consumers. However, the method for the simultaneous determination of EQ, EQI and EQDM in animal tissues is currently not available, and the accumulation extend of these chemicals in animal tissues after EQ administration remains to be evaluated. RESULTS: A gas chromatography-tandem mass spectrometry method was successfully developed for the simultaneous determination of EQ, EQI and EQDM in swine tissues. The quantitative limits of EQ, EQI and EQDM can achieve to 0.5, 5.0 and 5.0 µg/kg in swine tissues, respectively. The spiked-recovery ratios of the three analytes (5-2000 µg/kg) were in the range of 64.7%-100.7% with relative standard deviations below 11.6%. Moreover, the utilization of this method for the analysis of actual swine tissue samples revealed that the application of commercial EQ additive in swine diet would produce the residues of all the three chemicals (EQ, EQI and EQDM) in fat, kidney, liver and muscle. CONCLUSIONS: The assay accuracy and precision of this GC-MS/MS method can meet the requirement of quantitative analysis. Meanwhile, the safety of EQ as a feed additive should be seriously considered with regard to food safety concerns since the oxidation product of EQ may have potential carcinogenicity.

Rapid one-step enzyme immunoassay and lateral flow immunochromatographic assay for colistin in animal feed and food.

BACKGROUND: Colistin (polymyxin E) is a kind of peptide antibiotic which has been approved in animal production for the purposes of disease prevention, treatment, and growth promotion. However, the wide use of colistin in animal feed may accelerate the spread of colistin-resistance gene MCR-1 from animal production to human beings, and its residue in animal-origin food may also pose serious health hazards to humans. Thus, it is necessary to develop corresponding analytical methods to monitor the addition of colistin in animal feed and the colistin residue in animal-origin food. RESULTS: A one-step enzyme-linked immunosorbent assay (ELISA) and a lateral flow immunochromatographic assay (LFIA) for colistin were developed based on a newly developed monoclonal antibody. The ELISA showed a 50% inhibition value (IC50) of 9.7 ng/mL with assay time less than 60 min, while the LFIA had a strip reader-based detection limit of 0.87 ng/mL in phosphate buffer with assay time less than 15 min. For reducing the non-specific adsorption of colistin onto sample vial, the components of sample extraction solution were optimized and proved to greatly improve the assay accuracy. The spiked recovery experiment showed that the recoveries of colistin from feed, milk and meat samples were in the range of 77.83% to 113.38% with coefficient of variations less than 13% by ELISA analysis and less than 18% by LFIA analysis, respectively. Furthermore, actual sample analysis indicated that the two immunoassays can produce results consistent with instrumental analysis. CONCLUSIONS: The developed assays can be used for rapid qualitative or quantitative detection of colistin in animal feed and food.

Effects of guanidinoacetic acid on growth performance, creatine metabolism and plasma amino acid profile in broilers.

The objective of this study was to assess the effects of guanidinoacetic acid (GAA) on growth performance, creatine deposition and blood amino acid (AA) profile on broiler chickens. In Exp. 1, a total of 540 one-day-old Arbor Acres male broilers (average initial body weight, 45.23 ± 0.35 g) were divided randomly into five treatments with six replicates of 18 chicks each. Broilers were fed corn-soybean meal-basal diets supplemented with 0, 600, 800, 1,000 or 1,200 mg/kg GAA for 42 days respectively. Results showed that dietary GAA inclusion increased average daily gain (ADG) and improved gain-to-feed ratio (G:F) from 1 to 42 days (p < 0.01). However, average daily feed intake was unaffected by dietary supplementation of GAA. As GAA inclusion increased, the contents of creatine in plasma and kidney were increased (linear, p < 0.01), while the contents of GAA and creatine in liver were decreased (linear, p < 0.01). Similarly, GAA supplementation was inversely related to concentrations of most essential AA in plasma. In Exp. 2, a total of 432 one-day-old Arbor Acres male broilers (average initial body weight, 39.78 ± 0.58 g) were divided randomly into four treatments with six replicates of 18 chicks each. Birds were fed a corn-soybean meal-basal diet supplemented with 0, 200, 400 or 600 mg/kg GAA for 42 days respectively. Dietary inclusion of 600 mg/kg GAA significantly increased ADG and G:F of broilers (p < 0.05). In conclusion, dietary supplementation of 600-1,200 mg/kg GAA can effectively improve the growth performance in broiler chickens by affecting creatine metabolism and utilization efficiency of essential AA, and 600 mg/kg GAA is the minimum dose for improving performance.

MicroRNA expression profiles differ between primary myofiber of lean and obese pig breeds.

MicroRNAs (miRNAs) are non-coding small miRNAs ~22 nucleotides in length and play a vital role in muscle development by binding to messenger RNAs (mRNAs). Large White (LW, a lean type pig) and Meishan pigs (MS, a Chinese indigenous obese breed) have significant postnatal phenotype differences in growth rate, muscle mass and meat quality, and these differences are programmed during prenatal muscle development. Little research shed light directly on the miRNA transcriptome difference in prenatal muscles between these two distinct pig breeds. Myofiber phenotypes of LW and MS were measured at developmental stages of 35, 55 and 90 days post-conception (dpc), which revealed that the myogenesis process is more intense in MS than in LW at 35 dpc. To investigate the role of miRNAs involved in regulating muscle development at earlier stages of myogenesis and decipher the miRNAs transcriptome difference between LW and MS, here, the miRNAomes of longissimus dorsi muscle collected at 35 dpc from female LW and MS were analyzed by deep sequencing. Overall, 1147 unique miRNAs comprising 434 known miRNAs, 239 conserved miRNAs and 474 candidate miRNAs were identified. Expression analysis of the 10 most abundant miRNAs in every library indicated that functional miRNAome may be a small amount and tend to be greater expressed. These sets of miRNA may play house keeping roles that were involved in myogenesis. A total of 87 miRNAs were significantly differentially expressed between LW and MS (reads > 1000, P < 0.05). Gene ontology (GO) and KEGG pathway enrichment analysis revealed that the differentially expressed miRNAs (DE miRNAs) were associated mainly with muscle contraction, WNT, mTOR, and MAPK signaling pathways. Some myogenesis related miRNAs (miR-133, miR-1, miR-206 and miR-148a) are highly abundant in MS, while other miRNAs (let-7 family, miR-214, miR-181) highly expressed in LW. In addition, the expression patterns of miRNAs (miR-1, -133, -206) at three prenatal stages (35, 55 and 90 dpc) were determined using qRT-PCR. Notably, ssc-miR-133 was significantly more highly expressed in LW pigs skeletal muscle at all prenatal stages compared with its expression in LW pigs skeletal muscle. Taken together, the main functional miRNAs during muscle development are different between lean and obese pig breeds. The present study adds new information to existing data on porcine miRNAs and will be helpful to investigate the dominant (main functional) muscle-related miRNAs sets in different pig breeds.

Moderate Maternal Energy Restriction During Gestation in Pigs Attenuates Fetal Skeletal Muscle Development Through Changing Myogenic Gene Expression and Myofiber Characteristics.

Maternal undernutrition during gestation influences the development of the fetus, thereby increasing the risk of metabolic syndrome in adulthood. Skeletal muscle, one of the key insulin-responsive organs, is susceptible to maternal nutritional programming. This study aimed to evaluate the effect of moderate maternal energy restriction during gestation in pigs on basic events of fetal skeletal myogenesis. Primiparous, purebred Meishan sows were fed a control (normal energy intake) or a low-energy (LE) diet from mating to day 90 of gestation. Biochemical characteristics, myogenic gene expression, and myofiber characteristics were assessed in longissimus dorsi (LD) muscle of fetuses on days 55 and 90 of gestation. Fetal weights, myofiber density, and fetal umbilical vein serum triiodothyronine (T3) concentration decreased in LE group on both days 55 and 90 of gestation. The expression and activity of creatine kinase, the messenger RNA (mRNA) expression of myosin heavy chain ( MYH/ MyHC) genes ( MYH2 and MYH4), concentration of muscular DNA and protein, and protein expression of fast-MyHC isoforms were reduced in LD muscle of LE fetuses on day 55 or 90 of gestation. Meanwhile, myogenic gene expression was reduced in LE fetuses on day 55 or 90 of gestation, indicating the downregulation of myogenesis. Additionally, the exposure to LE diet led to increased isocitrate dehydrogenase activity and slow MyHC (MYH7) mRNA expression on day 90 of gestation, suggesting the elevation of oxidative muscle metabolism. These findings suggest that moderate energy restriction during gestation attenuates fetal skeletal muscle development in pigs, resulting in the delay of skeletal muscle differentiation and maturity.

Moderately increased maternal dietary energy intake delays foetal skeletal muscle differentiation and maturity in pigs.

OBJECTIVES: This study aimed to evaluate the effects of moderately increased maternal dietary energy intake during gestation on foetal skeletal muscle development and metabolism with pig as a model. METHODS: Twelve primiparous purebred Large White sows (initial body weight 135.5 ± 1.6 kg) were allocated to one of two energy intake treatments: normal-energy-intake group (Con, 30.96 MJ DE/day) as recommended by the National Research Council (NRC; 2012) and high-energy-intake group (HE, 34.15 MJ DE/day). The nutritional treatments were introduced from mating to day 90 of gestation. On day 90 of gestation, foetuses were examined by morphological, biochemical and molecular analysis of the longissimus muscle. Umbilical vein serum hormones were measured. RESULTS: Sow body weight was increased in HE group compared with Con group (P < 0.05), whereas foetal myofibre density was decreased (P < 0.05). Meanwhile, protein concentration, creatine kinase and lactate dehydrogenase activities and umbilical vein serum triiodothyronine (T3) concentration were decreased in HE foetuses (P < 0.05). Maternal HE diets decreased the mRNA abundance of muscle growth-related genes, myosin heavy-chain (MYH/MyHC) genes (MYH2 and MYH1) and insulin-like growth factor 1 and insulin growth factor-binding protein 5 (P < 0.05). Furthermore, the protein expressions of myogenic differentiation factor 1, myogenin and fast-MyHC isoforms were reduced in HE foetuses (P < 0.05). CONCLUSION: Our results suggest that moderately increased maternal dietary energy intake delays the differentiation and maturation in skeletal muscle of the foetus on day 90 of gestation.