Genome-wide association study identified five quantitative trait loci and two candidate genes for digestive traits in Suhuai pigs

This work aimed to identify markers and candidate genes underlying porcine digestive traits. In total, 331 pigs were genotyped by 80 K Chip data or 50 K Chip data. For apparent neutral detergent fiber digestibility, a total of 19 and 21 candidate single nucleotide polymorphisms (SNP) were respectively identified using a genome-wide efficient mixed-model association algorithm and linkage-disequilibrium adjusted kinship. Among them, three quantitative trait locus (QTL) regions were identified. For apparent acid detergent fiber digestibility, a total of 16 and 17 SNPs were identified by these two methods, respectively. Of these, three QTL regions were also identified. Moreover, two candidate genes (MST1 and LATS1), which are functionally related to intestinal homeostasis and health, were detected near these significant SNPs. Taken together, our results could provide a basis for deeper research on digestive traits in pigs.

Effects of Varying Levels of Wheat Bran Dietary Fiber on Growth Performance, Fiber Digestibility and Gut Microbiota in Erhualian and Large White Pigs

To evaluate the tolerance of a high-fiber diet in Erhualian pigs (Er-HL), the present investigation systematically investigated the ramifications of varying wheat bran fiber levels, specified as total dietary fiber (TDF) values of 14.07%, 16.32%, 17.99%, and 18.85%, on growth performance, fiber digestibility and gut microbiota in Er-HL, large Large White pigs (L-LW, the same physiological stage as the Er-HL) and small Large White pigs (S-LW, the same body weight as the Er-HL). Our results revealed that fiber levels exerted no discernable impact on growth performance (average daily feed intake (ADFI), and average daily gain (ADG)) of Er-HL (p > 0.05). Conversely, L-LW exhibited a decrease in ADFI and ADG with increasing fiber levels (p < 0.05). Notably, the apparent total tract digestibility (ATTD) of various fiber components, including neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicellulose, TDF and insoluble dietary fiber (IDF), in Er-HL were significantly higher than those in S-LW and L-LW irrespective of diets (p < 0.05). The ATTD of cellulose and hemicellulose in Er-HL significantly decreased with increasing fiber levels (p < 0.05), yet remained statistically indifferent when comparing the 7%-wheat-bran-replaced diet (7% WRB, TDF 16.32%) to the basal diet (TDF 14.07%) (p > 0.05). The cecal microbiota of Er-HL had higher richness estimators (Chao1 and ACE) than those of S-LW and L-LW irrespective of diets (p < 0.01). Breed serves as a pivotal determinant in shaping swine gut microbiota. Thirteen genera were selected as the key bacteria related to high fiber digestibility of Er-HL. Further functional examination of these key genera elucidated an enrichment of pathways pertinent to carbohydrate metabolism in Er-HL samples compared with S-LW and L-LW samples. In summary, Er-HL exhibited high-fiber tolerance both in terms of growth performance and fiber digestibility compared with Large White pigs. Specifically, the ATTD of NDF, ADF, hemicellulose, IDF and TDF were significantly higher in Er-HL compared with L-LW and S-LW, irrespective of diets. Fiber level exerted no discernable impact on growth performance (ADFI, ADG) and the ATTD of fiber (NDF, ADF, IDF and TDF) in Er-HL. The optimum fiber level of the Er-HL was identified as 7% WRB (TDF 16.32%). Thirteen genera were ascertained to significantly contribute to high fiber digestibility of Er-HL, correlating with an enhancement of carbohydrate metabolism pathways.

Effects of short-term feeding with high fiber diets on growth, utilization of dietary fiber, and microbiota in pigs

Finishing pigs can adapt to high-fiber diet smoothly according to the production performance and their intestinal microbiota through a 28-day trial or longer. However, it is unclear, at which stage during the experimental period, the adaptation occurred. Here we studied the dosage effects of dietary fiber (Total dietary fiber (TDF) from 16.70 to 24.11%) on growth performance, fiber digestibility, fecal microbiota, and microbial fermentation of finishing pigs during a 14-day feeding period. The results showed that the average daily feed intake (ADFI) and feed/gain (F/G) of pigs were not affected as the dietary fiber increased. Apparent total tract digestibility (ATTD) of cellulose, hemicellulose, insoluble dietary fiber (IDF), soluble dietary fiber (SDF), and TDF of pigs remained unchanged when TDF was between 16.70 and 17.75%, while strikingly decreased when TDF increased from 17.75 to 24.11%. It is worth noting that increasing fiber intake seemed to favor hemicellulose digestion. In addition, the increase in fiber intake increased fecal microbial diversity, especially improved the proportion of the members of the family Prevotellaceae, Ruminococcaceae, and Lachnospiraceae, and decreased the abundance of the genus Streptococcus. Moreover, the increase in fiber intake promoted the digestion of fiber, production of short chain fatty acids (SCFAs), and enhanced microbial pyruvate metabolism and butanoate metabolism. In conclusion, short-term high fiber feeding has no adverse effects on the growth performance of finishing pigs. ATTD of dietary fiber of finishing pigs was maintained when TDF was at 17.75%. And short-term high fiber feeding improved microbial diversity and fiber degradation functions of finishing pigs.

Metagenomic Analysis Reveals New Microbiota Related to Fiber Digestion in Pigs

Making full use of high fiber and low-cost crop coproducts is helpful to alleviate the situation of people and livestock competing for crops. Digestion of dietary fibers in pigs is mainly through microbial fermentation in the large intestine. To reveal microbiota related to fiber digestion in pigs, fecal samples have been collected from 274 healthy female Suhuai pigs at 160 days of age under the same feeding conditions and have measured apparent neutral detergent fiber (NDF) and acid detergent fiber (ADF) digestibility. Samples from Suhuai pigs with extreme high and low apparent NDF digestibility and extreme high and low apparent ADF digestibility were subjected to shotgun metagenomic sequencing. At the species level, 62 microbial species in H_NDF group and 54 microbial species in H_ADF group were related to high fiber digestibility. Among them, Lachnospiraceae bacterium 3-1 and Alistipes sp. CAG:514 may be new types of microorganisms associated with fiber digestion. In addition, we found that more abundant GH5 and GH48 family (contribute to cellulose degradation) genes, GH39 and GH53 family (contribute to hemicellulose degradation) genes in microorganisms may contribute to the higher apparent NDF digestibility of pigs, and more abundant GH3 and GH9 family (contribute to cellulose degradation) genes in microorganisms may contribute to the higher apparent ADF digestibility of pigs. The abundance of AA4 family (helps in lignin degradation) genes in H_NDF and H_ADF groups was significantly higher than that in L_NDF and L_ADF groups, respectively (P < 0.05). Three pathways in H_NDF group and four pathways in H_ADF group are important pathways associated with degradation of non-starch polysaccharides, and their relative abundance is significantly higher than that in L_NDF and L_ADF groups, respectively. Gut microbiota of Suhuai pigs with high apparent fiber digestibility had higher abundance of genes and microbiota related to fiber digestion and may have stronger fiber digestion potential compared with low apparent fiber digestibility group. This study revealed that the characteristics of gut microbiota and microbial gene functions of pigs with high fiber apparent digestibility, which provided a theoretical basis and reference for further understanding the impact of gut microbiota on fiber digestibility of pigs.

Effects of various levels of dietary fiber on carcass traits, meat quality and myosin heavy chain I, IIa, IIx and IIb expression in muscles in Erhualian and Large White pigs

This study evaluated the effects of bran fiber levels on carcass traits, meat quality and expression of myosin heavy chain isoform genes in muscles in Erhualian (Er-HL) and Large White pig (LW). Our results showed that fiber level did not affect carcass weight of Er-HL, while carcass weight of LW decreased with the increase of fiber level. Fiber level did not influence meat quality traits of LW, whereas increased fiber level led to an increase in pH_{45 min} of Er-HL, and Er-HL fed 7% bran fiber (BRC) increased redness of meat compared with control diet (CON). We observed a decreased MyHCIIb and MyHCIIx mRNAs and protein levels in Er-HL fed 7% BRC compared with those in other groups, accompanying with a tendency for increased mRNA abundance of MyHCI. The slow-twitch oxidative fiber (MyHCI) is rich in myoglobin and mitochondrial oxidative metabolic enzymes, and the increased expression of MyHCI fiber in pork has resulted in higher redness value. In summary, bran fiber had no adverse effect on the meat quality of LW and appropriate fiber level addition in diets could improve meat quality of Er-HL through regulation the expression of myofiber types.

Adding Appropriate Fiber in Diet Increases Diversity and Metabolic Capacity of Distal Gut Microbiota Without Altering Fiber Digestibility and Growth Rate of Finishing Pig

The digestion ability of pigs to dietary fiber is derived from their intestinal microbiota, especially hindgut microbiota. However, tolerance of pigs to high dietary fiber and the changes of microbiota profile with fiber levels are still unclear. To investigate the changes of gut microbiota with dietary fiber and its relationship with fiber digestibility, we conducted comparative analyses of growth rate, apparent fiber digestibility, gut microbiota and volatile fatty acid (VFA) profiles in Chinese Suhuai pigs feeding diets with different defatted rice bran (DFRB) fiber levels. We found that dietary fiber level had no effect on the growth rate of Suhuai pigs. Although the apparent digestibility of Cellulose, insoluble dietary fiber (IDF) and total dietary fiber (TDF) decreased with dietary fiber level, we found that the apparent digestibility of Cellulose, IDF and TDF of Suhuai pigs was not changed when provided with diet containing 19.10% TDF (as feed basis). The pigs provided with diet containing 19.10% TDF had higher microbial richness, proportions of several fiber-degrading bacteria taxa at genus level and predicted microbial functions (such as carbohydrate metabolism, energy metabolism) in cecum compared to those fed with basal diet. In addition, the fiber-induced increasing of fiber-degrading bacteria promoted the VFAs metabolism, which potentially helped Suhuai pigs to maintain growth rate. However, as TDF reached to 24.11% (as feed basis), the apparent digestibility of fiber decreased and the positive effect on intestine microbiota in caecum were absent. Together, our data suggest that appropriate fiber level could increase the diversity and metabolic capacity of distal gut microbiota to improve the utilization efficiency of fiber resources without altering the growth rate of pigs.

Defatted Rice Bran Supplementation in Diets of Finishing Pigs: Effects on Physiological, Intestinal Barrier, and Oxidative Stress Parameters

Simple Summary

Most studies on dietary fiber mainly focus on the digestibility of feed nutrients and microbial flora, etc. However, insufficient attention has been paid to the regulation of immune and oxidative stress of the intestinal tract by dietary fiber. This study investigated the effects of varying levels of defatted rice bran replacing corn on physiological, intestinal barrier, and oxidative stress parameters in finishing pigs. Based on the current findings, a high diet of rice bran will not only reduce the level of inflammatory factors in the peripheral blood of finishing pigs, but also enhance the healthy level of the colon through mucin2 and keap1-Nrf2 pathways. Our results can be used as reference for dietary rice bran to improve intestinal health in finishing pigs.

Abstract

Rice bran is a waste product with low cost and high fiber content, giving it an added advantage over corn and soybean meal, which have to be purchased and always at a relatively higher cost. Under the background of increased attention to sustainable agriculture, it is significant to find alternative uses for this byproduct. A total of 35 finishing pigs were allotted to five dietary treatments: a control group with basal diet and four experimental diets where corn was equivalently substituted by 7%, 14%, 21%, and 28% defatted rice bran (DFRB), respectively. With increasing levels of DFRB, the neutrophil to lymphocyte ratio (NLR) linearly decreased (p < 0.05). In the jejunum, the mRNA level of nuclear factor erythroid-2 related factor-2 (Nrf2) exhibited a quadratic response (p < 0.01) with incremental levels of DFRB. In the colon, the mRNA levels of mucin 2 (MUC2), Nrf2, and NAD(P)H: quinone oxidoreductase 1 (NQO1) were upregulated (linear, p < 0.05) and heme oxygenase-1 (HO-1) was upregulated (linear, p < 0.01). Overall, using DFRB to replace corn decreased the inflammatory biomarkers of serum and showed potential function in modulating the intestinal barrier by upregulating the mRNA expression levels of MUC2 and downregulating that of Nrf2, NQO1, and HO-1 in the colon.

Effects of Increasing Levels of Defatted Rice Bran on Intestinal Physical Barrier and Bacteria in Finishing Pigs

The aims of this study were to assess the effects of increasing levels of DFRB as a replacement for corns on intestinal physical barrier function and bacteria of finishing pigs. A total of 35 castrated finishing pigs (age: 158.5 ± 2.0 d, initial body weight: 62.9 ± 0.8 kg) were randomly divided into five dietary treatments (seven replicates/treatment) for a 28-day experimental period, i.e., a control diet with basal diet, and four experimental diets in which maize was replaced by 7%, 14%, 21%, and 28% DFRB, respectively. The results showed that serum endotoxins concentration and diamine oxidase (DAO) activity were both increased (linear, p = 0.0004, 0.001, respectively) with DFRB level. However, compared with control group, serum endotoxins concentration and DAO activity were not different in pigs fed with 7% DFRB in the diet. There was a quadratic response in serum D-lactate concentration to the increased DFRB (quadratic, p = 0.021). In the cecum, thickness of the intestinal wall significantly increased with increasing levels of DFRB in the diets (linear, p = 0.033), while crypt depth/thickness of the intestinal wall ratio significantly decreased with increasing level of DFRB in the diets (linear, p = 0.043). In the jejunum, total bacteria, Escherichia coli, and Bifidobacterium all responded quadratically to increasing levels of DFRB in the diets (quadratic, p = 0.003, 0.001, 0.006, respectively). Additionally, there was no difference in Escherichia coli in pigs fed 0%, 7%, and 14% DFRB diets. In the colon, there were quadratic responses in C. perfringens to the increased DFRB (quadratic, p = 0.023). C. perfringens reduced as the DFRB concentration increased from 0% to 14% and then increased. When D-lactate, total bacteria, Escherichia coli, Bifidobacterium, and C. perfringens were considered, the optimal substitution level of DFRB were 12.00%, 11.84%, 7.50%, 8.92%, and 15.92%, respectively. In conclusion, 7% DFRB had a beneficial effect on intestinal wall thickness, Bifidobacterium and C. perfringens, and had no adverse effect on intestinal permeability and Escherichia coli.

[Cell infiltration in nasal polyps and it's pathological significance]

OBJECTIVE

To study the relation between inflammatory cells infiltration in nasal polyp tissues and it's pathogenesis.

METHOD

Nasal mucosa from 10 normal individual and 4 patients of nasal polyps were studied with immunohistochemical technique and histopathologic examination.

RESULT

The number of eosinophils, CD68 positive cells and monocytes was significantly higher (P < 0.05) in nasal polyps tissues than in the normal controls.

CONCLUSION

Infiltration of inflammatory effector cells such as eosinphils and chronic inflammatory changes of the nasal mucosa might play a role in nasal polyps sprouting.

Capillary electrophoretic separation of cationic porphyrins

Cationic porphyrins have a wide variety of uses including those as nucleic acid binding and cleaving agents, as potential pharmacological agents, as electron donor/acceptors in intramolecular electron transfer processes and as analytical reagents. Herein, we report the separation of cationic porphyrins by capillary electrophoresis on fused silica in phosphate buffer at pH 2-5. The porphyrins studied in this work were synthesized from alkylation of the parent tetrapyridylporphyrin (TPyP) to give various pyridinium porphyrins. For example, methylation of TPyP gives a mixture of the mono-, cis-di-, trans-di-, tri- and tetramethylated porphyrins [e.g., 5,10,15,20-tetrakis(N-methyl-4-pyridiniumyl)-21H,23H-p orphyrin, TMPyP(4)]. Capillary electrophoresis on a synthetic mixture showed separation of four of these compounds. Mixtures after alkylation with iodopropionic acid and bromopropylamine were also separated. The cis-di- and trimethylated TMPyP derivatives were separated on a small preparative scale by centrifugal partition chromatography. Capillary electrophoresis was also used to separate metallo TMPyP(4) complexes including those of cobalt, copper, iron, manganese, palladium, tin, vanadium and zinc. The conformational isomers (atropisomers) of 5,10,15,20-tetrakis(N-methyl-2-pyridiniumyl)-21H,23H-p orphyrin, TMPyP(2), were also separated. Net charge, molecular mass and molecular shape all contribute to the differential retention of cationic porphyrins under capillary electrophoresis conditions. Additional factors affecting the separations, including aggregation and protonation of the porphyrins, were probed by evaluating the separation of TMPyP(4) and its butyl and octyl analogs as a function of solution conditions. Cationic porphyrins are difficult to separate using traditional chromatographic methods; capillary electrophoresis and centrifugal partition chromatography provide excellent new techniques for separation of this class of compounds.