Yuheng Luo

Lean Breed Landrace Pigs Harbor Fecal Methanogens at Higher Diversity and Density than Obese Breed Erhualian Pigs

The diversity of fecal methanogens of Erhualian (obese type) and Landrace (lean type) pigs was examined using separate 16S rRNA gene libraries for each breed. A total of 763 clones were analyzed; 381 from the Erhualian library and 382 from the Landrace library were identified belonging to the genus Methanobrevibacter. Others were identified belonging to the genus Methanosphaera. The two libraries showed significant differences in diversity (P < 0.05) and composition (P < 0.0001). Only two operational taxonomic units (OTUs) were found in both libraries, whereas six OTUs were found only in the Erhualian library and 23 OTUs were found only in the Landrace library. Real-time PCR showed that the abundance of fecal methanogens in Landrace pigs was significantly higher than that in Erhualian pigs (P < 0.05). Results showed that the Landrace pig (lean) harbored a greater diversity and higher numbers of methanogen mcrA gene copies than the Erhualian pig (obese). These differences may be related to the fatness or leanness in these two pig breeds. The results provide new leads for further investigations on the fat storage of pigs or even humans.

Broilers fed dietary vitamins harbor higher diversity of cecal bacteria and higher ratio of Clostridium, Faecalibacterium, and Lactobacillus than broilers with no dietary vitamins revealed by 16S rRNA gene clone libraries

Research on the interaction between dietary vitamins and intestinal bacteria is poorly understood. To investigate the effect of dietary vitamins on the cecal bacterial communities, 2 bacterial 16S rRNA gene clone libraries were constructed from pooled PCR products obtained from the cecal digesta of 28-d broilers fed diets with vitamins (V) at the NRC level or with no vitamins (NV). The results showed that BW gain and average feed intake of V broilers was significantly higher (P < 0.01) than NV broilers, whereas the feed/gain ratio was significantly lower (P < 0.01) in V broilers. A total of 188 and 185 clones were sequenced for the NV and V broilers, respectively. Sequence identity criterion of 98% was used to assign sequences to operational taxonomic units (OTU). Clones from the NV group broilers were assigned to 14 OTU, with 33% clones affiliated with the genus Clostridium, 19% affiliated with the genera Escherichia/Shigella, 14% affiliated with the genus Bacteroides, and the remaining clones (34%) affiliated with 5 other bacterial genera (Faecalibacterium, Parasporobacterium, Ruminococcus, Streptococcus, and Subdoligranulum). Clones from the V group broilers were assigned to 23 OTU, with 46% of the clones affiliated with the genus Clostridium, 11% affiliated with the genus Fecalibacterium, and the remaining clones (43%) affiliated with 8 other genera (Anaerofilum, Lactobacillus, Anaerotruncus, Oscillibacter, Alistipes, Gracilibacter, Acetivibrio, and Haloplasma). Three OTU assigned to Clostridium, Faecalibacterium, and Ruminoccus were shared between the 2 libraries. Shannon diversity index showed the V broilers exhibited significantly higher bacterial diversity (P = 0.05), and Libshuff analysis indicated that the community structure between the 2 groups was significantly different (P < 0.0001). These results suggest that lack of dietary vitamins can increase the ratio of facultative pathogenic bacteria and decrease the diversity of bacteria in the cecum of broilers. Our results provide new leads for further investigations on the interaction between dietary vitamin additives and the gut health of broilers.

Effects of dietary gossypol concentration on growth performance, blood profiles, and hepatic histopathology in meat ducks

The objective of this study was to determine the effects of gossypol from cottonseed meal (CSM) on growth performance, blood biochemical profiles, and liver histopathology of ducks. A total of 900 1-d-old ducks were randomly allocated to 5 treatments with 12 pens/treatment and 15 ducks/pen. The 5 experimental diets were formulated in such a way that 0% (a corn-soybean meal basal diet, diet 1), 25% (diet 2), 50% (diet 3), 75% (diet 4), and 100% (diet 5) of protein from soybean meal were replaced with that from CSM. All diets were formulated on a digestible amino acid basis. The experiment included 2 phases, the starter phase (1 to 3 wk) where the test diets contained graded levels of CSM and the growth phase (4 to 5 wk) where birds were fed a corn-soybean basal diet to examine the recovery of ducks after CSM withdrawal. Dietary CSM and gossypol linearly (P < 0.01) and quadratically (P < 0.01) decreased ADG and ADFI during d 1 to 14. The threshold of daily total gossypol (TG) and free gossypol (FG) intake based on ADG on d 1 to 7 and d 7 to 14 were 32.20 and 2.64 mg/d, and 92.12 and 9.62 mg/d, respectively. Serum alanine aminotransferase increased (P < 0.05) linearly with increasing level of gossypol in the diets (d 7), whereas aspartate aminotransferase increased (P < 0.05) linearly and quadratically (d 14). Serum albumin concentration decreased (P < 0.05) quadratically with increasing dietary CSM concentrations on d 21. The degree of damage to the liver increased markedly with increasing dietary CSM and gossypol content and the length of CSM and gossypol intake. On d 35, there was no difference on BW and blood profiles of ducks among all treatments. These results suggest that meat ducks’ dietary TG and FG concentration should be lower than 928.9 and 77.2 mg/kg, respectively, during d 1 to 21 of age and that a 2-wk withdrawal of diets containing gossypol should be considered.

Role of the insulin-like growth factor system in epiphyseal cartilage on the development of Langshan and Arbor Acres chickens, Gallus domesticus

We measured the mRNA transcript expression patterns for members of the insulin-like growth factor (IGF) system during embryonic and postnatal development in epiphyseal cartilage from Langshan (LS) and Arbor Acres (AA) chickens. Insulin-like growth factor binding protein (IGFBP)-2 expression was positively correlated with IGF-I from embryonic day (E) 14 to postnatal d (P) 0 and with IGF-II from E14 to P14 but negatively correlated with IGF-I from P0 to P42 and IGF-II from P14 to P42. Expression of IGFBP-5 correlated positively with IGF-I from E14 to P0 but negatively from P0 to P28. The results suggest that these genes are regulated in a coordinated fashion during development. A negative correlation was found between IGFBP-7 and IGF-II during P0 to P42. A positive correlation was found between IGFBP-3 (E14 to E18, P14 to P42) and IGF-IR and between IGFBP-3 (E14 to P0, P14 to P42) and IGF-I. The endocrine factors can be integrated with nutrition to regulate animal growth. In our study, AA chickens were fed a nutrient-rich AA diet, and LS chickens were fed either an AA diet or a less-rich diet. The LS and AA chickens fed the same AA diet showed no differences in IGF-I, IGF-I receptor, IGFBP-2, IGFBP-5, IGFBP-7, and IGFBP-3 but did still show differences in IGF-II. Our data indicate that these select genes may show linked expression during certain periods of development and that differences in gene expression respond differently to nutrient intake in LS and AA chickens.

The response of meat ducks from 15 to 35 d of age to gossypol from cottonseed meal

The objective of this study was to investigate the responses of meat ducks of 15 to 35 d of age to free gossypol (FG) from cottonseed meal (CSM) and to establish the maximum limits of dietary FG concentration based on growth performance, blood parameters, and tissue residues of gossypol. Nine hundred 15-d-old ducks were randomly allocated to 5 treatments with 10 cages/treatment and 18 ducks/cage on the basis of BW. Five isonitrogenous and isocaloric experimental diets were formulated on a digestible amino acid basis to produce diets in which 0% (without FG), 25% (36 mg FG/kg), 50% (75 mg FG/kg), 75% (111 mg FG/kg), and 100% (153 mg FG/kg) of protein from soybean meal were replaced by that from CSM. Increasing dietary FG content, BW, and ADG decreased (linearly, P < 0.05, except for ADG of days 29 to 35), and F/G linearly increased (P < 0.05). At 35 d, blood hemoglobin, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration linearly decreased (P < 0.05), while serum total protein, albumin, and globulin content linearly decreased (P < 0.05), and the residue of gossypol in liver, kidney, heart, breast, and leg muscle linearly increased (P < 0.001) with increases in dietary FG concentration. Ducks fed 36 mg FG/kg (5.83% CSM of diet) diet had a normal histological structure of liver, and muscle (breast and leg) had no residue of gossypol. The maximum limit of dietary FG concentration was estimated to range from a low of 36 mg/kg to maximize serum globulin concentration to a high of 124 mg/kg to minimize feed intake for 22 to 28d on the basis of a quadratic broken-line model.

The effects of maternal dietary vitamin premixes, canthaxanthin, and 25-hydroxycholecalciferol on the performance of progeny ducklings

This trial studied the effects of maternal dietary vitamin premixes, and the mixture of canthaxanthin (CX) and 25-hydroxycholecalciferol (25-OH-D3) on the performance of progeny ducklings. Four maternal diets were used under a 2 × 2 factorial arrangement with 2 kinds of vitamin premixes (Regular and High; High premix had higher levels of all vitamins except K3 than the Regular premix), and with or without the addition of the mixture of CX (6 mg/kg) and 25-OH-D3 (0.069 mg/kg). Cherry Valley duck breeders (38-wk-old) were fed with corn-wheat flour-soybean meal-based diets for 8 wk, and then eggs were collected and hatched. Healthy ducklings (equal number of female and male) from each maternal group were randomly selected and received the same commercial starter (1 to 14 d) and grower (15 to 35 d) pellet diet for 35 d. Maternal High vitamin premix increased shank pigmentation (1 d, P = 0.001), BW (1 d, P < 0.001 and 14 d, P = 0.006), BW gain (1 to 14 d, P = 0.008), G:F ratio (1 to 14 d, P = 0.007), superoxide dismutase (SOD; 1 d liver, P = 0.027 and 14 d serum, P = 0.031), and total antioxidant capacity (1 d liver, P < 0.001); and decreased protein carbonyl (14 d serum, P = 0.011) of ducklings. The mixture of CX and 25-OH-D3 increased yolk pigmentation (P < 0.001); increased shank pigmentation (1 d, P < 0.001 and 14 d, P < 0.001), BW (1 d, P < 0.001), feed intake (15-35 d, P = 0.014), SOD (1 d liver, P = 0.032), and tibia ash (14 d, P = 0.010) of ducklings; and decreased malondialdehyde (P < 0.001) and protein carbonyl (P = 0.044) of yolks, and malondialdehyde (14 d serum, P < 0.001) of ducklings. In conclusion, either maternal High vitamin premix or maternal supplementation of the CX and 25-OH-D3 mixture improves growth performance and antioxidant status of ducklings.

Effects of dietary canthaxanthin and 25-hydroxycholecalciferol supplementation on the antioxidant status and tibia quality of duck breeders and newly hatched ducklings

This study evaluated the effects of dietary canthaxanthin (CX) and 25-hydroxycholecalciferol (25-OH-D3) supplementation on the antioxidant status and tibia quality of duck breeders and newly hatched ducklings. In total, 780 female and 156 male duck breeders were randomly allotted to 2 treatments. Duck breeders were fed either a commercial diet (containing 3,000 IU/kg vitamin D3) or the same diet plus a mixture of CX (6 mg/kg) and 25-OH-D3 (0.069 mg/kg) for 40 wk. The antioxidant status of duck breeders, egg yolk, and ducklings; tibia quality of duck breeders and ducklings; and shell quality of breeder eggs were investigated. The total antioxidant capacity of breeder female liver (P = 0.028), breeder male testis (P = 0.049), egg yolk (P = 0.032), one-day-old duckling liver (P = 0.024), and one-day-old duckling yolk sac (P = 0.012) were increased by dietary supplementation of the mixture of CX and 25-OH-D3 The inclusion of CX and 25-OH-D3 decreased liver protein carbonyl of breeder females (P = 0.030), and liver malonaldehyde (P = 0.050) and protein carbonyl (P = 0.030) of breeder males. Yolk (P < 0.001), shank (P < 0.001), and yolk sac pigmentation (P < 0.001) of one-day-old ducklings were increased by the supplementation of the CX and 25-OH-D3 mixture. No differences (P > 0.05) were observed in tibia quality or eggshell quality between treatments. In conclusion, the inclusion of the mixture of CX and 25-OH-D3 in a diet sufficient in vitamin D3 increased antioxidant status but not tibia quality of duck breeders and newly hatched ducklings.

Different Types of Dietary Fibers Trigger Specific Alterations in Composition and Predicted Functions of Colonic Bacterial Communities in BALB/c Mice

Soluble dietary fibers (SDF) are fermented more than insoluble dietary fibers (IDF), but their effect on colonic bacterial community structure and function remains unclear. Thus, bacterial community composition and function in the colon of BALB/c mice (n = 7) fed with a high level (approximately 20%) of typical SDF, oat-derived β-glucan (G), microcrystalline cellulose (M) as IDF, or their mixture (GM), were compared. Mice in group G showed a lowest average feed intake (p < 0.05) but no change on the average body weight gain (p > 0.05) compared to other groups, which may be associated with the highest concentration of colonic propionate (p < 0.05) in these mice. The bacterial α-diversity of group G was significantly lower than other groups (p < 0.01). In group G, the relative abundance of bacteria belonging to the phylum Bacteroidetes was significantly increased, whereas bacteria from the phylum Firmicutes were significantly decreased (p < 0.01). The core bacteria for different treatments showed distinct differences. Bacteroides, Dehalobacterium, and Prevotella, including known acetogens and carbohydrate fermenting organisms, were significantly increased in relative abundance in group G. In contrast, Adlercreutzia, Odoribacter, and Coprococcus were significantly more abundant in group M, whereas Oscillospira, Desulfovibrio, and Ruminoccaceae, typical hydrogenotrophs equipped with multiple carbohydrate active enzymes, were remarkably enriched in group GM (p < 0.05). The relative abundance of bacteria from the three classes of Proteobacteria, Betaproteobacteria, Gammaproteobacteria (including Enterobacteriaceae) and Deltaproteobacteria, were significantly more abundant in group G, indicating a higher ratio of conditional pathogenic bacteria in mice fed dietary β-glucan in current study. The predicted colonic microbial function showed an enrichment of “Energy metabolism” and “Carbohydrate metabolism” pathways in mice from group G and M, suggesting that the altered bacterial community in the colon of mice with the two dietary fibers probably resulted in a more efficient degradation of dietary polysaccharides. Our result suggests that the influence of dietary β-glucan (SDF) on colonic bacterial community of mice was more extensively than MCC (IDF). Co-supplementation of the two fibers may help to increase the bacterial diversity and reduce the conditional pathogens in the colon of mice.

Fungi in Gastrointestinal Tracts of Human and Mice: from Community to Functions

Fungi are often ignored in studies on gut microbes because of their low level of presence (making up only 0.1% of the total microorganisms) in the gastrointestinal tract (GIT) of monogastric animals. Recent studies using novel technologies such as next generation sequencing have expanded our understanding on the importance of intestinal fungi in humans and animals. Here, we provide a comprehensive review on the fungal community, the so-called mycobiome, and their functions from recent studies in humans and mice. In the GIT of humans, fungi belonging to the phyla Ascomycota, Basidiomycota and Chytridiomycota are predominant. The murine intestines harbor a more diverse assemblage of fungi. Diet is one of the major factors influencing colonization of fungi in the GIT. Presence of the genus Candida is positively associated with dietary carbohydrates, but are negatively correlated with dietary amino acids, proteins, and fatty acids. However, the relationship between diet and the fungal community (and functions), as well as the underlying mechanisms remains unclear. Dysbiosis of intestinal fungi can cause invasive infections and inflammatory bowel diseases (IBD). However, it is not clear whether dysbiosis of the mycobiome is a cause, or a result of IBD. Compared to non-inflamed intestinal mucosa, the abundance and diversity of fungi is significantly increased in the inflamed mucosa. The commonly observed commensal fungal species Candida albicans might contribute to occurrence and development of IBD. Limited studies show that Candida albicans might interact with immune cells of the host intestines through the pathways associated with Dectin-1, Toll-like receptor 2 (TLR2), and TLR4. This review is expected to provide new thoughts for future studies on intestinal fungi and for new therapies to fungal infections in the GIT of human and animals.

Effects of MicroRNA-27a on Myogenin Expression and Akt/FoxO1 Signal Pathway during Porcine Myoblast Differentiation

ABSTRACT Skeletal myoblast differentiation is controlled by a multitude of transcription factors and signal pathways. Myogenin is a critical transcriptional regulator in the initiation and maintenance of myoblast differentiation. The Akt/FoxO1 signal pathway plays an important role in myoblast differentiation. MicroRNAs are a kind of small noncoding RNAs that have been regarded as important regulators in skeletal muscle cell proliferation and differentiation. The objective of this study was to investigate the effects of microRNA-27a (miR-27a) on myogenin expression and Akt/FoxO1 signal pathway during porcine myoblast differentiation. Here, we found that the expression of miR-27a was gradually diminished at the early differentiation stage and then rebounded. Overexpression of miR-27a suppressed the mRNA and protein expression levels of myogenin during porcine myoblast differentiation, whereas inhibition of miR-27a promoted the mRNA and protein expression levels of myogenin. In addition, overexpression of miR-27a decreased the level of P-Akt/Akt and increased the protein level of FoxO1; however, inhibition of miR-27a increased the level of P-Akt/Akt and decreased the protein level of FoxO1. The present study demonstrated that miR-27a could inhibit myogenin expression and Akt/FoxO1 signal pathway during porcine myoblast differentiation.