Bovine pestiviruses include Pestivirus A (BVDV-1), Pestivirus B (BVDV-2), and Pestivirus H, which was originally called HoBi-like pestivirus. We conducted an epidemiological investigation for pestiviruses circulating in backyard cattle farms in central China. RT-PCR assays and sequences analysis were conducted on 54 nasal swabs, 26 serum samples, and three lung samples from cattle with respiratory infections and identified 29 pestivirus strains, including 24 Pestivirus A and five Pestivirus H strains. Phylogenetic analysis based on partial 5’-UTR and Npro sequences showed that the genotypes of 24 Pestivirus A strains included Pestivirus A 1b (6 isolates), Pestivirus A 1m (6 isolates), Pestivirus A 1q (2 isolates), Pestivirus A 1u (1 isolates), and Pestivirus A 1o (9 isolates, a putative new sub-genotype). In addition, a single “Pestivirus H a” genotype included all five Pestivirus H strains. This study revealed extensive genetic variations within bovine pestivirus isolates derived from cattle in backyard farms in Central China, and this epidemiological information improves our understanding of the epidemics of bovine Pestiviruses, as well as will be useful in designing and evaluating diagnostic methods and developing more effective vaccines.

Context: The rearing system is a critical non-genetic factor that can considerably affect poultry production. Aims: This study examined the effects of floor rearing systems (FRS), net rearing systems and cage rearing systems (CRS) on growth performance, carcass traits, meat quality and serum biochemical parameters of Gaoyou ducks. Methods: A total of 450 healthy 22-day-old male Gaoyou ducks with similar average bodyweight were randomly divided into the FRS, net rearing systems and CRS groups. The experiment lasted from 22 to 84 days of age. Key results: CRS ducks had a higher final bodyweight, average daily feed intake and average daily gain, and a lower feed-to-gain ratio P < 0.05). FRS ducks had higher breast and gizzard yields and shear force, and lower drip loss and abdominal fat content (P < 0.05). Moreover, FRS ducks had significantly lower glucose, total protein and triglyceride, and higher high-density lipoprotein cholesterol levels (P < 0.05). Conclusions: CRS was beneficial to the growth performance of Gaoyou ducks, whereas FRS was beneficial to carcass traits, meat quality and some serum biochemical parameters. Implications: The results indicated that the CRS and FRS had their own advantages. Thus, an appropriate rearing system should be selected according to the production target and market demand.

Waterfowl semen cryopreservation technology is a key link in genetic resource conservation and artificial breeding, but poultry spermatozoa, due to their unique morphology and biochemical properties, are prone to oxidative stress during freezing, resulting in a significant decrease in vitality. In this study, we first used four different freezing procedures (P1–P4) to freeze duck semen and compared their effects on duck sperm quality. Then, the changes in antioxidant indexes in semen were monitored. The results showed that program P4 (initial 7 °C/min slow descent to −35 °C, followed by 60 °C/min rapid descent to −140 °C) was significantly better than the other programs (p < 0.05), and its post-freezing sperm vitality reached 71.41%, and the sperm motility was 51.73%. In the P1 and P3 groups, the sperm vitality was 65.56% and 53.41%, and the sperm motility was 46.99% and 31.76%, respectively. In terms of antioxidant indexes, compared with the fresh semen group (CK), the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-px) in the P2 group were significantly decreased (p < 0.05), while the activities of SOD and CAT in the P4 group showed no significant changes (p > 0.05) except that the activity of GSH-px was significantly decreased (p < 0.05). And the CAT and GSH-px activities in the P4 group were significantly higher than those in the P2 group (p < 0.05). The content of malondialdehyde (MDA) in the P2 group was significantly higher than that in the fresh semen group (p < 0.05), and there was no significant difference between the P2 group and the P4 group (p > 0.05). The total antioxidant capacity (T-AOC) content of the P2 and P4 groups was significantly lower than that of the fresh semen group (p < 0.05). The staged cooling strategy of P4 was effective in reducing the exposure time to the hypertonic environment by balancing intracellular dehydration and ice crystal inhibition, shortening the reactive oxygen species accumulation and alleviating oxidative stress injury. On the contrary, the multi-stage slow-down strategy of P2 exacerbated mitochondrial dysfunction and the oxidative stress cascade response due to prolonged cryogenic exposure time. The present study confirmed that the freezing procedure directly affects duck sperm quality by modulating the oxidative stress pathway and provides a theoretical basis for the standardization of duck semen cryopreservation technology.

Context: Residual feed intake (RFI) is an important indicator for feed efficiency (FE) in poultry nutrition. Aims: The present study assessed the impact of RFI on the growth performance, carcass traits, meat quality, and blood biochemical parameters of Cherry Valley ducks. Methods: One thousand healthy male ducks at the age of 14 days were housed in individual cages until slaughter at the age of 42 days. The carcass yield, meat quality, and blood biochemical parameters of 40 ducks with the highest RFI (HRFI) and 40 ducks with the lowest RFI (LRFI) were determined. Key results: For growth performance, RFI, feed conversion ratio (FCR), and average daily feed intake (ADFI) were considerably lower in the LRFI group than in the HRFI group, whereas no significant differences were observed in bodyweight (BW) or bodyweight gain (BWG). In terms of carcass traits and meat quality, the LRFI group had lower abdominal fat content and shear force, and a higher L* value, whereas there were no remarkable differences in other carcass and meat-quality traits between the two groups. For serum biochemical parameters, serum concentrations of cholecystokinin (CCK) and adrenocorticotropic hormone (ACTH) were significantly higher and total cholesterol (TC) and insulin (INS) concentrations were significantly lower in the LRFI group than in the HFRI group. Conclusions: These outcomes suggest that choosing Cherry Valley ducks according to low RFI can enhance FE and some serum biochemical indices, without affecting their production performance, and it can reduce abdominal fat content. Implications: Our results showed that RFI is a useful tool for breeders to select more efficient ducks for breeding. Future research should focus on exploring how genetic improvements could lead to lower RFI values in ducks, which could enhance the sustainability of the poultry industry.

Objectives: The aim of this experiment was to explore how the addition of Schizochytrium powder to the feeding ration affected the production performance, egg quality, and antioxidant function of chickens. Schizochytrium powder is a unicellular spherical marine microalga that can be cultivated through heterotrophic fermentation, with characteristics including rapid cell growth, stable composition, and ease of large-scale production. Experimental design: Three hundred and twenty 33-week-old chickens with similar egg production rates and body weights were selected and randomly divided into four groups, with five replicates each and 16 hens in each replicate. The control group (Group I) was fed a corn–soybean meal basal diet, while the test groups were supplemented with 0.5% (Group II), 1.0% (Group III), and 2.0% (Group IV) Schizochytrium powder on top of this basal diet, respectively. The pretest period was 1 week, and the main test period was 8 weeks. The results revealed the following: (1) Compared with Group I, the average daily feed intake (ADFI) and laying rate (LR) were significantly lower (p < 0.05) in Group IV, and there was no significant difference (p > 0.05) in the ADFI and LR between Groups II and III. (2) Compared with Group I, the eggshell strength (ES) and docosahexaenoic acid (DHA) content of Groups II, III, and IV were significantly higher (p < 0.05). (3) Compared with Group I, serum triglyceride (TG) content was significantly decreased (p < 0.05), and serum low-density lipoprotein (LDL) content was significantly increased (p < 0.05) in Groups II, III, and IV. Serum total antioxidant capacity (T-AOC), superoxide dismutase (SOD), and peroxidase (PO) activities were significantly higher (p < 0.05) and serum malondialdehyde (MDA) content was significantly lower (p < 0.05) in Groups II, III, and IV compared to Group I. In conclusion, adding Schizochytrium powder to the feeding ration could affect chickens’ production performance, increase egg DHA content, and improve the antioxidant capacity of the organism. Based on the results of this study, we recommend a ratio of 1.0% Schizochytrium powder addition.

Waterfowl semen cryopreservation technology is a key link in genetic resource conservation and artificial breeding, but poultry spermatozoa, due to their unique morphology and biochemical properties, are prone to oxidative stress during freezing, resulting in a significant decrease in vitality. In this study, we first used four different freezing procedures (P1-P4) to freeze duck semen and compared their effects on duck sperm quality. Then, the changes of antioxidant indexes in semen were monitored. The results showed that program P4 (initial 7°C/min slow descent to -35℃, followed by 60°C/min rapid descent to -140℃) was significantly better than the other programs (P < 0.05), and its post-freezing sperm vitality reached 71.41%, and the sperm motility was 51.73%. In terms of antioxidant indexes, compared with the fresh semen group (CK), the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-px) in the P2 group were significantly decreased (P < 0.05), while the activities of SOD and CAT in the P4 group showed no significant changes (P > 0.05) except that the activity of GSH-px was significantly decreased (P < 0.05). And the CAT and GSH-px activities in P4 group were significantly higher than those in P2 group (P < 0.05). The content of malondialdehyde (MDA) in P2 group was significantly higher than that in fresh semen group (P < 0.05), and there was no significant difference between P2 group and P4 group (P > 0.05). The total antioxidant capacity (T-AOC) content of P2 and P4 groups was significantly lower than that of fresh semen group (P < 0.05). The staged cooling strategy of P4 was effective in reducing the exposure time to the hypertonic environment by balancing intracellular dehydration and ice crystal inhibition, shortening the reactive oxygen species accumulation and alleviate oxidative stress injury. On the contrary, the multi-stage slow-down strategy of P2 exacerbated mitochondrial dysfunction and oxidative stress cascade response due to prolonged cryogenic exposure time. The present study confirmed that the freezing procedure directly affects duck sperm quality by modulating the oxidative stress pathway, and provides a theoretical basis for the standardization of duck semen cryopreservation technology.