Owing to the practical interest in understanding duration of fertility (DF) to reduce the cost of producing hatching eggs by decreasing the frequency of artificial insemination, as well to uncover the mechanism of the estrogen-gut microbiome axis, elucidating the interaction between the maternal microbiome and the function of sperm storage tubules (SST) has become important for revealing the DF in laying hens. In this study, we investigated the compositional, structural, and functional differences in gut microbiomes between hens with high (HSST, n = 8) and low SST activity (LSST, n = 10) by performing phenotypic selection from approximately 400 individual hens based on their DFs. Their cecal microbial communities were analyzed by sequencing the V4 region of the 16S rRNA gene. The microbiome abundance estimators from the ceca of HSST and LSST hens were not significantly different at the phylum and genus taxonomic levels, although the relative abundances for the phylum Firmicutes and the genus Lactobacillus were higher in the HSST group. Furthermore, some taxonomic levels of bacteria expressing the components of several metabolic pathways differed between the HSST and LSST groups. Moreover, predicting functional microbiomes by Kyoto Encyclopedia of Genes and Genomes (KEGG) revealed that certain pathways, such as the metabolism of carbohydrates and protein, cellular processes, and organismal systems, of the HSST group exhibited higher expression of genes associated with bioactivity and energy biosynthesis than those in the LSST group. Our results may provide insights into hen-microbe interactions with respect to DF and will be useful in establishing a strategy for new research to uncover the functional regulation of SST in laying hens.

This study was aimed at estimating the dietary manganese (Mn) requirement for laying duck breeders. A total of 504 Longyan duck breeders (body weight: 1.20 ± 0.02 kg) aged 17 wk were randomly allocated to 6 treatments. The birds were fed a basal diet (Mn, 17.5 mg/kg) or diets supplemented with 20, 40, 80, 120 or 160 mg/kg Mn (as MnSO4·H2O) for 18 wks. Each treatment had 6 replicates of 14 ducks each. As a result of this study, dietary Mn supplementation did not affect the productive performance of laying duck breeders in the early laying period (17 to 18 wk), but affected egg production, egg mass and feed conversion ratio (FCR) from 19 to 34 wk (P 0.05), and there was a linear and quadratic effect of supplement level (P 0.05). The proportion of pre-ovulatory ovarian follicles increased (P 0.01) linearly and quadratically, and atretic follicles (weight and percentage) decreased (P 0.05) quadratically with dietary Mn supplementation. The density and breaking strength of tibias increased (quadratic; P 0.05), the calcium content of tibias decreased (linear, quadratic; P 0.01), and Mn content increased (linear, quadratic; P 0.001) with increasing Mn. The addition of Mn had a quadratic effect on serum contents of estradiol, prolactin, progesterone, luteinizing hormone and follicle-stimulating hormone (P 0.001). Dietary Mn supplementation decreased serum contents of total protein (linear, P 0.05), glucose (quadratic, P 0.05), total bilirubin, triglycerides, total cholesterol, low-density lipoprotein cholesterol and calcium (linear, quadratic; P 0.05). The serum total antioxidant capacity, and total and Mn-containing superoxide dismutase activities increased (linear, quadratic; P 0.001), and malondialdehyde content decreased (linear, quadratic; P 0.001) in response to Mn supplemental levels. The dietary Mn requirements, in mg/kg for a basal diet containing 17.5 mg/kg Mn, for Longyan duck breeders from 19 to 34 weeks of age were estimated to be 84.2 for optimizing egg production, 85.8 for egg mass, and 95.0 for FCR. Overall, dietary Mn supplementation, up to 160 mg/kg feed, affected productive performance, tibial characteristics, serum biochemical and antioxidant status of layer duck breeders. Supplementing this basal diet (17.5 mg/kg Mn) with 85 to 95 mg/kg additional Mn was adequate for laying duck breeders during the laying period.

This study evaluated the effects of different dietary zinc (Zn) levels on productive and reproductive performance, egg quality, tibial characteristics, plasma biochemical and antioxidant indices, and zinc deposition in laying duck breeders. A total of 504 Longyan duck breeders aged 21 wk were randomly allocated to 6 treatments and fed a basal diet (Zn, 27.7 mg/kg) or that basal diet supplemented with Zn (as ZnSO4·H2 O) at 10, 20, 40, 80, or 160 mg Zn per kg of feed for 20 wk. Each group had 6 replicates of 14 ducks each. Dietary Zn supplementation affected (P 0.05) the egg production, FCR, and shell thickness of laying duck breeders from 21 to 40 wk, and there was a quadratic (P 0.05) effect between them. Dietary Zn supplementation affected (P 0.05) and quadratically (P 0.001) increased the breaking strength, density, and dry defatted weight of tibias. Alkaline phosphatase, calcium, phosphorus, total superoxide dismutase, glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) activities or content in plasma were affected (P 0.05), and quadratically (P 0.01) changed by dietary Zn levels. Dietary Zn supplementation affected (P 0.01) and increased the Zn deposition in egg yolk (linear, P 0.05; quadratic, P 0.001) and tibia (linear, P 0.05). The dietary Zn requirements, in mg/kg for a basal diet containing 27.7 mg/kg Zn, for Longyan duck breeders from 21 to 40 wk of age were estimated to be 65.4 for optimizing egg production, 68.6 for FCR, 102 for hatchling BW, 94.7 for eggshell thickness, 77.2 for tibial breaking strength, 81.4 for tibial density, 78.9 for tibial dry defatted weight, 69.5 for plasma GSH-Px activity, 72.4 for plasma MDA content, and 94.6 for Zn content in tibia. Overall, dietary Zn supplementation, up to 160 mg/kg feed, affected the productive performance, eggshell thickness, tibial characteristics, plasma antioxidant status, and Zn deposition of layer duck breeders. Supplementing this basal diet (27.7 mg/kg Zn) with 70 to 80 mg/kg additional Zn was adequate for laying duck breeders during the laying period.

This study evaluated the optimal concentrations of dietary Se for the productive and reproductive performance, tibial quality, and antioxidant status in duck breeders aged 23 to 49 wk. In total, 432 Longyan duck breeders aged 22 wk were allotted randomly to 6 treatments, each with 6 replicates of 12 individually caged birds. The experiment lasted for 27 wk, and birds were fed corn-soybean meal-based diets containing 0.11, 0.19, 0.27, 0.35, 0.43, or 0.51 mg Se/kg, respectively. The tested dietary Se levels did not affect egg production and tibial quality of duck breeders. The Se contents of the shell, yolk or albumin, whole egg, and the fertility of set eggs increased in a linear and quadratic manner (P 0.05) in response to the increased dietary Se level, whereas the yolk malondialdehyde (MDA) and embryonic mortality decreased. The activities of glutathione peroxidase 3 (Gpx3) in plasma and Gpx1 in the erythrocytes and livers of breeder ducks increased in a linear and quadratic manner (P 0.05) in response to increased dietary Se levels, whereas the total superoxide dismutase (T-SOD) activity increased and the MDA concentration decreased in the liver. The activity of Gpx3 in the plasma and Gpx1 in the erythrocytes and livers of newly hatched ducklings increased linearly (P 0.01) with the increase in Se level, whereas the T-SOD activity and MDA concentration did not change. In conclusion, diets containing 0.27 mg Se/kg led to the highest egg fertility and hatchability in Longyan duck breeders, and using levels >0.19 mg Se/kg diet enhanced the antioxidant capacity in breeders and their offspring. The regression model indicated that dietary Se levels 0.19, 0.27, 0.28, 0.24, and 0.30 mg/kg are optimal levels to obtain maximum Se deposition efficiency in eggs, egg fertility, Gpx1 activity in erythrocytes and liver in duck breeders, and plasma activity of Gpx3 in newly hatched ducklings, respectively.

NULL

Ovarian follicle selection is a natural biological process in the pre-ovulatory hierarchy in birds that drives growing follicles to be selected within the ovulatory cycle. Follicle selection in birds is strictly regulated, involving signaling pathways mediated by dietary nutrients, gonadotrophic hormones and paracrine factors. This study aimed to test the hypothesis that dietary Ca may participate in regulating follicle selection in laying ducks through activating the signaling pathway of cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA)/extracellular signal-regulated kinase (ERK), possibly mediated by gonadotrophic hormones. Female ducks at 22 weeks of age were initially fed one of two Ca-deficient diets (containing 1.8% or 0.38% Ca) or a Ca-adequate control diet (containing 3.6% Ca) for 67 days (depletion period), then all birds were fed the Ca-adequate diet for an additional 67 days (repletion period). Compared with the Ca-adequate control, ducks fed 0.38% Ca during the depletion period had significantly decreased (P 0.05) numbers of hierarchical follicles and total ovarian weight, which were accompanied by reduced egg production. Plasma concentration of FSH was decreased by the diet containing 1.8% Ca but not by that containing 0.38%. The ovarian content of cAMP was increased with the two Ca-deficient diets, and phosphorylation of PKA and ERK1/2 was increased with 0.38% dietary Ca. Transcripts of ovarian estradiol receptor 2 and luteinizing hormone receptor (LHR) were reduced in the ducks fed the two Ca-deficient diets (P 0.05), while those of the ovarian follicle stimulating hormone receptor (FSHR) were decreased in the ducks fed 0.38% Ca. The transcript abundance of ovary gap junction proteins, A1 and A4, was reduced with the Ca-deficient diets (P 0.05). The down-regulation of gene expression of gap junction proteins and hormone receptors, the increased cAMP content and the suppressed hierarchical follicle numbers were reversed by repletion of dietary Ca. These results indicate that dietary Ca deficiency negatively affects follicle selection of laying ducks, independent of FSH, but probably by activating cAMP/PKA/ERK1/2 signaling pathway.

The present study was conducted to evaluate the effects of dietary addition of capsaicin (CAP) on egg production performance, follicular development and ovarian antioxidant capacity in laying ducks. Three hundred and seventy eight 58-week-old laying ducks were randomly divided into three treatments, each treatment was consisted of 6 replicates, with 12 individually caged laying ducks per replicate. Ducks fed a basal diet served as control, the other two groups of ducks were fed the same diet containing 150 mg/kg CAP, but in the manner of feed restriction (pair-fed) or ad libitum ad libitum fed. The experiment lasted for 8 weeks. The results showed that the dietary supplementation with capsaicin under condition of free intake increased feed intake (P 0.001), and tended (P 0.1) to increase egg production and egg weight in laying ducks, but had no effects on daily egg mass and feed conversion ratio. The relative weight of large yellow follicles from the two CAP-supplemented groups at 64 wk of age were significantly higher than that of controls (P = 0.01). The relative weight of the small yellow follicles in the CAP free-fed group was significantly higher than that of the other two groups (P 0.01). CAP supplementation under ad libutum fed conditions tended to increase the number of dominant follicles in laying ducks (P = 0.06). The ovarian mRNA expression of TRPV4, ATP2A2, ITPR1, and CaM in the CAP ad libitum fed groups were significantly higher than those of the other two groups (P 0.05). The ovarian mRNA expression of CDK1 in CAP free-fed ducks was significantly higher than that of the other two groups (P = 0.01). CAP supplementation significantly increased the plasma Gpx activity (P 0.01) in comparison to the control group, but reduced the MDA content in the ovaries of laying ducks (P 0.01). The results of this study indicates that dietary supplementation of CAP increased feed intake and improved egg production performance probably by activating calcium signaling pathway and improving redox status.

The multiscale structural, physicochemical, and digestible properties of potato starch before and after heat–moisture treatment were investigated, and further compared between repeated heat–moisture treatment (RHMT) and continuous heat–moisture treatment (CHMT). After heat–moisture treatment, there appeared partial disruption and pits on the starch granules, and the birefringence edges of HMT starch particles became blurred. Besides, the molecular weight of samples conspicuously decreased after two kinds of treatments. The crystal type of HMT starches transformed from B‐type to C‐type according to X‐ray analysis. A decrease in the solubility and swelling power in high temperatures were identified. The pasting temperature, the gelatinization transition temperature (To, Tp, Tc), and the slowly digestible starch (SDS) content of HMT starches were significantly higher than native potato starch, while the peak viscosity, the trough viscosity, the final viscosity, the breakdown, and the gelatinization enthalpy (ΔH) of RHMT and CHMT potato starches decreased compared to the native. RHMT potato starches displayed significantly higher relative crystallinity degree and gelatinization transition temperatures. The cooling process of RHMT in which the linkage between the recombinant amylose/amylopectin was enhanced compared with CHMT, which contributed to that RHMT potato starches exhibited greater advantages in practical applications.

Naked barley grains were germinated at 25 °C for 12, 24, and 36 h, followed by hot air and infrared drying. Changes in structural, physicochemical, and functional properties of naked barley flour and starch after germination and drying were evaluated. Germinated and dried flour showed loose structure in starch granules surface. Germination and drying enhanced bulk density and water solubility of flour, while oil absorption capacity decreased. Treated barley starch showed greater water holding capacity, viscosity, and gelatinization temperature than those of native ones, and the maximum increase in water holding capacity of germinated barley was 20.25% of the native ones. Moreover, molecular weight, amylopectin long chains, and crystallinity of treated starch decreased, and the maximum decrease in the crystallinity of germinated barley was 78.36% of the native ones. Generally, germination for 24 and 36 h by infrared drying induced significant changes of flour and starch compared with hot air drying ones. Therefore, the combination of germination and infrared drying can be suggested as a promising method for modifying the properties of naked barley flour and starch to promote their application in the food industry.

Three distyryl-containing compounds, namely, 2-((cyanomethyl)thio)-4,6-distyrylnicotinonitrile (2), 3-amino-4,6-distyrylthieno[2,3- b]pyridine-2-carbonitrile (3) and 2-((2-cyanoethyl)thio)-4,6-distyrylnicotinonitrile (4) have been prepared and characterized by elemental and spectroscopic analyses. The three compounds contain the pyridine moiety and are considered neonicotinoids analogues. Because neonicotinoids were considered the most effective pesticides, the biological activity of the distyryl-containing compounds as potential insecticides against cowpea aphid, Aphis craccivora Koch was evaluated. The agricultural bioactivity results of these compounds showed that the insecticidal activity varied from good to moderate against cowpea aphid insects.