Effects of different rearing systems on growth performance, carcass traits, meat quality and serum biochemical parameters of Chaohu ducks

Effects of coated sodium butyrate on the growth performance, serum biochemistry, antioxidant capacity, intestinal morphology, and intestinal microbiota of broiler chickens

Introduction

This study examined the impact of adding coated sodium butyrate (CSB) to the diet on the growth performance, serum biochemistry, antioxidant capacity, intestinal morphology, and cecal microbiota of yellow-feathered broiler chickens.

Methods

In this study, 240 yellow-feathered broiler chickens at 26 days old were divided into two groups: the control group (CON group) received a standard diet, and the experimental group (CSB group) received a diet with 0.5 g/kg of a supplement called CSB. Each group had 6 replicates, with 20 chickens in each replicate, and the experiment lasted for 36 days.

Results

Compared to the CON group, the CSB group showed a slight but insignificant increase in average daily weight gain during the 26-62 day period, while feed intake significantly decreased. The CSB group exhibited significant increases in serum superoxide dismutase, catalase, and total antioxidant capacity. Additionally, the CSB group had significant increases in total protein and albumin content, as well as a significant decrease in blood ammonia levels. Compared to the CON group, the CSB group had significantly increased small intestine villus height and significantly decreased jejunal crypt depth. The abundance of Bacteroidetes and Bacteroides in the cecal microbiota of the CSB group was significantly higher than that of the CON group, while the abundance of Proteobacteria, Deferribacteres, and Epsilonbacteraeota was significantly lower than that of the CON group.

Conclusion

These results suggest that adding CSB to the diet can improve the growth performance and antioxidant capacity of yellow-feathered broiler chickens while maintaining intestinal health.

Effects of cage vs. net-floor mixed rearing system on goose spleen histomorphology and gene expression profiles

Due to the demands for both environmental protection and modernization of the goose industry in China, the traditional goose waterside rearing systems have been gradually transitioning to the modern intensive dryland rearing ones, such as the net-floor mixed rearing system (MRS) and cage rearing system (CRS). However, the goose immune responses to different dryland rearing systems remain poorly understood. This study aimed to investigate and compare the age-dependent effects of MRS and CRS on the splenic histomorphological characteristics and immune-related genes expression profiles among three economically important goose breeds, including Sichuan White goose (SW), Gang goose (GE), and Landes goose (LD). Morphological analysis revealed that the splenic weight and organ index of SW were higher under CRS than under MRS (p < 0.05). Histological observations showed that for SW and LD, the splenic corpuscle diameter and area as well as trabecular artery diameter were larger under MRS than under CRS at 30 or 43 weeks of age (p < 0.05), while the splenic red pulp area of GE was larger under CRS than under MRS at 43 weeks of age (p < 0.05). Besides, at 43 weeks of age, higher mRNA expression levels of NGF, SPI1, and VEGFA in spleens of SW were observed under MRS than under CRS (p < 0.05), while higher levels of HSPA2 and NGF in spleens of LD were observed under MRS than under CRS (p < 0.05). For GE, there were higher mRNA expression levels of MYD88 in spleens under CRS at 30 weeks of age (p < 0.05). Moreover, our correlation analysis showed that there appeared to be more pronounced positive associations between the splenic histological parameters and expression levels of several key immune-related genes under MRS than under CRS. Therefore, it is speculated that the geese reared under MRS might exhibit enhanced immune functions than those under CRS, particularly for SW and LD. Although these phenotypic differences are assumed to be associated with the age-dependent differential expression profiles of HSPA2, MYD88, NGF, SPI1, and VEGFA in the goose spleen, the underlying regulatory mechanisms await further investigations.

Effect of different free-range systems on the growth performance, carcass traits, and meat quality of Yangzhou geese

This study was conducted to investigate the effects of different free-range systems on the growth performance, carcass traits, and meat quality of geese. Grass pasture zones in the study area were selected, and 28 d-old male Yangzhou geese with similar body weights (1.57 ± 0.12 kg) were randomly allocated to one of three conditions: (A) free-range conditions in the apron area during 9:00 a.m.-4:00 p.m. (10-20 m from shed with grass pasture); (B) free-range conditions in the outer range from 9:00 a.m. to 4:00 p.m. (beyond 50 m from shed with grass pasture); and (C) barn system. Free range-reared geese had higher weight gain after 42 days of age than barn-reared geese, regardless of the range area. A lower feed conversion ratio was found in outer range-reared and apron area-reared geese from 28 to 63 days of age. In addition, the highest percentages of leg and breast muscle weights were observed in outer range-reared and apron area-reared geese, respectively. Finally, outer-range rearing resulted in a lower pH and lower moisture content. Therefore, these data suggest that the outer range system benefits growth performance and feed conversion ratio of geese and results in a higher percentage of leg muscle weight, lower pH, and lower moisture content.

Effects and Mechanisms of Cage versus Floor Rearing System on Goose Growth Performance and Immune Status

Currently, FRS and CRS are the two predominant dryland rearing systems in the goose industry. However, the effects of these two systems on goose growth performance and health, as well as the underlying mechanisms, have not been fully clarified. Thus, this study aimed to compare growth performance and immune status, as well as investigate the genome-wide transcriptomic profiles of spleen in geese, between CRS and FRS at 270 d of age. Phenotypically, the body weight and body size traits were higher in geese under FRS, while the weight and organ index of spleen were higher in geese under CRS (p < 0.05). Noticeably, the bursa of Fabricius of geese under FRS was degenerated, while that under CRS was retained. At the serum level, the immune globulin-G (IgG) and interleukin-6 (IL-6) levels were higher in geese under CRS (p < 0.05). At the transcriptomic level, we identified 251 differentially expressed genes (DEGs) in the spleen between CRS and FRS, which were mainly enriched in scavenger receptor activity, inflammatory response, immune response, neuroactive ligand-receptor interaction, phenylalanine metabolism, ECM receptor interaction, calcium signaling pathway, phenylalanine, tyrosine, and tryptophan biosynthesis, regulation of actin cytoskeleton, and MAPK signaling pathways. Furthermore, through protein-protein interaction (PPI) network analysis, ten candidate genes were identified, namely, VEGFA, FGF2, NGF, GPC1, NKX2-5, FGFR1, FGF1, MEIS1, CD36, and PAH. Further analysis demonstrated that geese in CRS could improve their immune ability through the "phenylalanine metabolism" pathway. Our results revealed that the FRS improved growth performance, whereas the CRS improved goose immune function by increasing levels of IL-6 and IgG in serum. Moreover, the phenylalanine metabolism pathway could exert positive effects on immune function of geese under CRS. These results can provide reliable references for understanding how floor and cage rearing systems affect goose growth performance and immune capacity.

Effects of indoor and outdoor rearing system on geese biochemical parameters and cecal microbial composition

The present study aimed to investigate the impact of indoor and outdoor rearing systems on the biochemistry and microbial composition of White Roman geese, with a particular focus on the gut microbiome. Our results showed that geese reared in an outdoor system had significantly lower serum aspartate aminotransferase (AST) compared to those reared indoors, but lower levels of high-density lipoprotein (HDL) and higher levels of low-density lipoprotein (LDL). Moreover, the cecal microbiota of geese reared outdoors exhibited higher species evenness and increased alpha diversity, with a significant alteration in the F/B ratios. The bacterial taxonomy composition also differed between the 2 rearing systems, with higher relative abundances of the Firmicutes and Actinobacteria and lower relative abundances of the Bacteroidetes and Proteobacteria in the outdoor system. These findings suggest that rearing systems may play a critical role in shaping the gut microbiome and overall health of geese. Notably, our data demonstrated that indoor rearing was associated with a higher abundance of pathogenic genera and a lower abundance of commensal genera compared to outdoor rearing. Our study supports the hypothesis that rearing systems may alter the physiological functions and microbial composition of geese, and highlights the need for further research to confirm and expand upon these findings. In summary, our study underscores the importance of considering the impact of rearing systems on the gut microbiome and health of geese.

Effects of Dietary Supplementation of Chinese Yam Polysaccharide on Carcass Composition, Meat Quality, and Antioxidant Capacity in Broilers

The study aimed to evaluate the influences of the dietary supplementation of Chinese yam polysaccharide (CYP) on the carcass performance, antioxidant capacity, and meat quality of broilers. Three hundred and sixty healthy 1-day-old broilers with similar body weight (39 ± 1 g, gender balanced) were randomly divided into four groups (control, CYP1, CYP2, and CYP3 groups). In the control group, broilers were fed a basal diet with CYP, and the CYP1, CYP2, and CYP3 groups were fed diets supplemented with 250, 500, and 1000 mg/kg CYP, respectively. There were three replicates in each group, 30 birds in each replicate, and the feeding trial lasted for 48 days. Statistical analysis was performed using SPSS 17.0 (SPSS Inc., Chicago, IL, USA) by one-way analysis of variance. The results showed that compared with the control group, dietary supplementation with 500 mg/kg CYP can improve live weight, half-eviscerated carcass percentage, eviscerated carcass percentage, and thigh muscle percentage. Moreover, dietary supplementation with 500 mg/kg CYP can improve the contents of total antioxidant capacity (T-AOC), total superoxide dismutase (T-SOD), glutathione peroxidase (GPX), and glutathione s-transferase (GST) in serum (p < 0.05). Meanwhile, the mRNA expression levels of nuclear factor-erythroid 2-related factor 2 (Nrf2), heme oxygenase 1 (HO-1), quinone oxidoreductase (NQO1), superoxide dismutase 1 (SOD1), glutathione peroxidase 1 (GPX1), and catalase (CAT) in the liver; the mRNA expression levels of HO-1, NQO1, GPX1, and CAT in the breast muscle; and the mRNA expression levels of NQO1, SOD1, and CAT in the thigh muscle of broilers in the CYP2 group were significantly increased (p < 0.05). In addition, the yellowness and shear force of the thigh and breast muscles and the content of malondialdehyde (MDA) in the serum of broilers in the control group were higher than that in the CYP2 groups (p < 0.05). The results demonstrated that the CYP2 group had the best effect on improving meat quality. In conclusion, dietary supplementation with 500 mg/kg CYP can improve the meat quality of broilers by improving carcass quality, meat color, shear force, and antioxidant capacity.

Proteomic analysis of the liver regulating lipid metabolism in Chaohu ducks using two-dimensional electrophoresis

In this study, we aimed to characterize the liver protein profile of Chaohu ducks using two-dimensional electrophoresis and proteomics. The livers were quickly collected from 120 healthy, 84-day-old Chaohu ducks. The intramuscular fat (IMF) content of the left pectoralis muscle was determined using the Soxhlet extraction method. The total protein of liver tissues from the high and low IMF groups was extracted for proteomics. Functional enrichment analysis of the differentially expressed proteins (DEPs) was conducted using gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG). In total, 43 DEPs were identified. Functional enrichment analysis indicated that these DEPs were significantly related to four lipid metabolic processes: carboxylic acid metabolic process, ATP metabolic process, oxoacid metabolic process, and organic acid metabolic process. Three pathways correlated with lipid metabolism were identified using KEGG analysis: glycolysis/gluconeogenesis, pentose phosphate pathway, fructose, and mannose metabolism. Eight key proteins associated with lipid metabolism were identified: ALDOB, GAPDH, ENO1, RGN, TPI1, HSPA9, PRDX1, and GPX1. Protein–protein interaction analysis revealed that the glycolysis/gluconeogenesis pathway mediated the interaction relationship. Key proteins and metabolic pathways were closely related to lipid metabolism and showed a strong interaction in Chaohu ducks.

Effects of different duck rearing systems on egg flavor and quality and microbial diversity

The fishy odor of duck eggs has restricted their consumption and industrial development, a problem that producers need to address. We estimated the effects of cage, floor, and pond rearing systems on duck egg flavor, egg quality, and microbial diversity by evaluating yolk trimethylamine (TMA) content, egg quality, and the differences between duck cecum (cage cecum, CC; floor cecum, FC; pond cecum, PC) and the environment (cage environment, CE; floor environment, FE; pond environment, PE). The results show that the yolk TMA content of the floor-rearing and pond-rearing systems was significantly higher than that of the cage-rearing system (P < 0.001), with no difference between the floor and pond-rearing systems. No significant differences were detected in egg quality among the rearing systems. Firmicutes, Actinobacteria, and Bacteroidetes were the dominant phyla in the cecum, and in the rearing environment, Firmicutes, Actinobacteria, Bacteroidetes, and Proteobacteria were the dominant phyla. The results of α and β diversity analyses show that changes in the rearing system affected the composition and diversity of duck cecal microbes. In addition, we screened several genera that may be related to the production of TMA in duck cecum under different rearing systems using LEfSe analysis; for example, Subdoligranulum in the CC group; Romboutsia in the FC group; and Lactobacillus, Clostridium, and Streptococcus in the PC group. In conclusion, the rearing system affects the cecal microbes of ducks, which in turn affect the deposition of TMA in duck eggs but have no adverse effect on egg quality. This study provides a basis for the development of rearing strategies to reduce the fishy odor of egg yolk in the duck industry.

Assessing growth performance, morphometric traits, meat chemical composition and cholesterol content in four phenotypes of naked neck chicken

The present study was conducted to assess the growth performance, morphometric traits, muscle chemical composition and cholesterol content in four phenotypes of naked neck chicken (black, white-black, light brown and dark brown). A total of 320-day-old chicks, 80 from each phenotype, were randomly stratified into 20 replicates (16/replicate), according to a completely randomized design. The results showed higher final body weight, weight gain, and better FCR in both light brown and dark brown phenotypes whereas time of gains was found to be greater in dark brown phenotype. Keel length and shank circumference were greater in dark brown whereas wing spread was found to be higher in light brown phenotype. Drumstick circumference and body length did not show any significant differences (P > 0.05) across the phenotypes. Dry matter was found to be higher in white black, crude protein in black, white black and dark brown, moisture in light brown, and cholesterol content in black whereas ether extract and ash content were found to be greater in black and white black phenotypes. In conclusion, both light brown and dark brown phenotypes showed superior growth performance and morphometric traits. Similarly, from a health point of view, the dark brown and light brown phenotypes seem superior because their cholesterol content was low. Thus, it is strongly recommended that there should be a conscious effort to improve economically important traits of the light and dark brown birds to be used as dual-purpose slow growing chicken, especially in developing countries.

Effects of rearing systems on production performance, antioxidant capacity and immune status of meat ducks at different ages

As potential substitutes for traditional free-range rearing system, floor-rearing system (FRS) and net-rearing system (NRS) are the current predominant dryland duck rearing systems. However, the influence of these two systems on production performance and duck health is poorly understood. In this study, a 2 × 3 factorial arrangement with two rearing systems (FRS and NRS) and three ages (4w, 8w and 13w) was conducted to study the effects of FRS and NRS on production, antioxidant capacity and immune status of Nonghua ducks. The production performance was mainly affected by the effect of rearing systems at 8w. Body weight, average daily gain, eviscerated weight and semi-eviscerated weight were higher in NRS ducks at 8w, but carcass yield at 8w and 13w was decreased (P < 0.05). Lipid deposition was enhanced in NRS and higher sebum and abdominal fat yields were seen at 8w and 13w (P < 0.05). NRS resulted in developmental retardation of the liver at 4w and decreased gizzard index at all ages (P < 0.05). Antioxidant capacity indicators were unaffected by rearing systems (P > 0.05), however, in NRS, slightly better antioxidant capacity was seen at 4w, while glutathione peroxidase (GSH-Px) activity was higher at 13w (P < 0.05). NRS ducks had higher thymus weight at 8w and higher spleen weight at 13w (P < 0.05). Immune cytokines were extensively affected by rearing system (P < 0.05) and higher levels of interferon-γ, interleukin-1β, interleukin-4 and immunoglobulins were seen in NRS ducks. Serum biochemical parameters (aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP)) showed that NRS was better for liver health, and in the liver of FRS ducks, ALP was higher at 13w, and both ALP and interferon-γ were higher at 13w than at 4w and 8w (P < 0.05). In conclusion, this study showed that NRS was, to an extent, conducive to production performance and duck liver health, but compared to FRS, defects were seen in visceral organ development and lipid deposition. Although antioxidant capacity was not significantly affected, NRS ducks may have better antioxidant capacity at the early breeding stage, and GSH-Px activity was increased for scavenging excess free radicals at the later one. NRS increased serum levels of interferon-γ, interleukin-1β, interleukin-4 and immunoglobulins and promoted thymus and spleen development, thus improving duck immune function. These findings will provide a reliable reference for selecting a rearing system.

Effect of sodium butyrate on slaughter performance, serum indexes and intestinal barrier of rabbits

The purpose of this study was to investigate the effect of sodium butyrate on slaughter performance, serum indexes and the intestinal barrier in rabbits. Six hundred healthy weaned rabbits were randomly divided into three groups (5 replicates per group, 40 rabbits per replicate): control (fed a basal diet), sodium butyrate (fed a basal diet containing 0.5% sodium butyrate) and antibiotic (fed a basal diet containing 0.004% antibiotic). The trial lasted 35 days, including 7 days of pretesting and 28 days of formal testing. The results showed that dietary sodium butyrate supplementation increased the full-bore weight, the half-bore weight and the half-bore rate of rabbits. Meanwhile, the content of aspartate aminotransferase (AST) in serum was increased in rabbits fed the sodium butyrate diet. According to the intestinal barrier, after adding sodium butyrate to feed, the tight junction function of the rabbit intestine is enhanced, and the intestinal microbial composition is also improved. To sum up, after sodium butyrate was added to feed instead of antibiotics, slaughter performance was significantly enhanced, serum indexes were improved, and intestinal barrier function was also enhanced. Therefore, sodium butyrate can be added to feed as an additive and can replace antibiotics.

Effects of Different Non-Cage Housing Systems on the Production Performance, Serum Parameters and Intestinal Morphology of Laying Hens

This study investigated the effects of plastic-net housing system (NRS) and floor-litter housing system (LRS) on the production performance, serum parameters and intestinal morphology of Shendan laying hens. A total of 1200 30-week-old hens were randomly allocated to the NRS and LRS groups, each of which included five replicates with 120 chickens in each replicate. The experiment was conducted from 32 to 40 weeks of age. Indoor airborne parameters were measured every 2 weeks, and indoor ground contamination was measured monthly. The laying rate and mortality of hens were recorded daily, and egg quality traits and serum parameters were measured every 2 weeks. At 40 weeks of age, four birds per replicate from each experimental group were selected for intestinal morphological observation. The results showed that the airborne bacteria number in the LRS was significantly higher than that in the NRS (p < 0.05) for most of the experimental period (except at 32 and 38 weeks of age), and the bacterial numbers on the surfaces of the floor and floor eggs in the LRS were approximately 10 times higher than those in the NRS (p < 0.05). Compared with the LRS, the NRS improved the laying rate (p < 0.05), reduced serum malondialdehyde (MDA) (p < 0.05) and corticosterone (CORT) concentrations and increased serum glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities, indicating favourable effects on antioxidative status. The NRS was significantly associated with an increased villus height (VH), villus height to crypt depth ratio (VCR) in the small intestine (p < 0.05) and increased VCR in the caecum (p < 0.05). Overall, the lower rate of bacterial contamination in the NRS than in the LRS indicated better environmental hygiene. The NRS enhanced the laying performance and antioxidant capacity of hens and was superior to the LRS in improving intestinal health. The current findings support the advantages of the NRS for the health and welfare of Shendan chickens during the peak laying period.

Dietary Beta-Hydroxy-Beta-Methyl Butyrate Supplementation Affects Growth, Carcass Characteristics, Meat Quality, and Serum Metabolomics Profile in Broiler Chickens

This study aimed to explore the effects of beta-hydroxy-beta-methyl butyrate (HMB) on serum metabolic profiles and meat quality of muscles in Wenshi broiler chickens. Birds were fed a basal diet with an additional 0, 0.05, 0.10, or 0.15% HMB, respectively. Results showed that dietary HMB quadratically increased the average daily gain (P = 0.058) and decreased feed:gain (P < 0.05) mainly in the starter phase. At 51 days of age, birds receiving 0.10% HMB diet exhibited less abdominal fat and more breast yield than the control (P < 0.05). Moreover, dietary HMB quadratically decreased the L^∗ value and drip loss in selected muscles (P < 0.05) and increased the a^∗ value in breast muscle (P < 0.05). Serum metabolome profiling showed that the most differentially abundant metabolites are lipids and lipid-like molecules, including phosphatidylcholines. It was concluded that HMB improved growth performance and meat quality of muscle in broilers.

Effects of rearing system and narasin on growth performance, gastrointestinal development, and gut microbiota of broilers

This study was conducted to evaluate the effects of 3 rearing systems (FL: flooring litter rearing, MC: multilayer cage rearing, PN: plastic net rearing) with or without supplemental narasin on growth performance, gastrointestine development and health of broilers. A total of 2,400 one-day-old Ross 308 mixed-sex broilers (1:1 ratio of males and females) were used in a completely randomized design utilizing a 3 × 2 factorial arrangement of treatments, with 12 replicates per treatment. Each replicate for FL, MC, and PN consisted of 34 birds per floor pen, 30 birds per cage, and 36 birds per net pen, respectively, ensuring the same stocking density (12 birds/m²) across the 3 systems. Results showed that lower ADG (average daily gain), ADFI (average daily feed intake), and FCR (feed conversation ratio) observed in the MC group than those of the other 2 systems from 1 to 36 d of age (P < 0.05). Narasin inclusion in the diets decreased ADFI and FCR significantly (P < 0.05). Multilayer cage and PN rearing systems reduced the relative weight of the gizzard significantly (P < 0.05). Compared with FL, MC reduced the relative weight of the duodenum, jejunum, and ileum (P < 0.05). The mRNA expression levels of the ileal IL-1β and IFN-γ in FL were higher than those in PN and MC (P < 0.05). Narasin decreased the ileal mRNA expression of TNF-α (P < 0.05). Different rearing systems changed the ileal microflora structure of broilers. The FL system increased the ileal microbial diversity of broilers and the relative abundance of Actinobacteria. Narasin combined with MC increased the relative abundance of Proteobacteria. In conclusion, birds reared in PN had a higher body weight. The MC birds had poorer intestinal development and health condition, higher abundance of Proteobacteria, but better FCR. The FL rearing appeared to be propitious for gastrointestinal development and health. Narasin inclusion in the diets improved FCR and changed the relative abundance Proteobacteria of broilers.

Effects of Rearing Conditions and Sex on Cecal Microbiota in Ducks

The intestinal microbiome influences the health of animals. However, little is known about the impact of indoor conditions and sex on intestinal microbiome diversity and composition in ducks. The present study aimed to investigate differences in the cecal microbiome between male and female ducks reared on the floor (PY group) or in cages (LY group). We also determined the relationships between cecal microbiota composition and slaughter traits, and the expression levels of mucosal and intestinal structural genes in ducks. There was a slight difference in slaughter traits among the groups, with cecum weight being significantly lighter in the LY compared with the PY group, especially in females (p < 0.05). Analysis of the alpha diversity of the cecal microbiota between males and females in the LY and PY groups showed that LY males had significantly lower diversity and richness. Beta diversity analysis demonstrated differences in the microbiota composition in relation to rearing conditions, and a significant difference between the sexes in the PY groups. The dominant bacterial phyla in duck cecum were Bacteroidetes, Firmicutes, Proteobacteria, and Fusobacteria. The relative abundances of the most common bacteria revealed that the intestinal microbiota diversity and composition were affected by both feeding conditions and sex. Several bacterial genera were detected differentially among the groups. These genera were correlated with slaughter traits and expression levels of mucosal and cecal structural genes in ducks. In conclusion, rearing conditions, sex, and associated changes in the cecal microbiota are thus associated with gut barrier functions in ducks.

Effects of different rearing systems on intramuscular fat content, fatty acid composition, and lipid metabolism-related genes expression in breast and thigh muscles of Nonghua ducks

Rearing system is a critical nongenetic factor influencing meat quality of ducks. In this study, a total of 360 birds were randomly allocated into floor rearing system (FRS) and net rearing system (NRS) to compare their effects on intramuscular fat (IMF) deposition, fatty acid composition, and related gene expression in muscles of Nonghua ducks. Sawdust bedding and stainless mesh bed were equipped in FRS and NRS, respectively. At the eighth week (8w) and 13th week (13w), the breast and thigh muscles of ducks were collected to determine the profiles of lipids composition and the expressions of lipid metabolism-related genes. The IMF content was higher in 13w-FRS than 8w-FRS and 8w-NRS in breast muscle, whereas it was higher in 13w-NRS than other groups in thigh muscle (P < 0.05). C16:1, C20:5(n-3) of muscles were higher in 8w-NRS than 8w-FRS, whereas C18:1(n-9)c, C18:2(n-6)c, Ʃ monounsaturated fatty acid (MUFA), and ƩMUFA/Ʃsaturated fatty acid (SFA) ratio of muscles were higher in 13w-NRS than 8w-FRS and 8w-NRS (P < 0.05). C22:6(n-3), C20:4(n-6) of breast muscle and C20:3(n-6) of thigh muscle were higher in 13w-NRS than 13w-FRS (P < 0.05). Fatty acids variation was studied by principal component analysis, exhibiting extensive positive loadings on principal components. SREBP1, ACADL, and FABP3 were downregulated in breast muscle, whereas PPARα and ELOVL5 were upregulated in thigh muscle of NRS ducks at 13w. Principal components were extensively correlated with lipids composition parameters, and principal components of breast muscle 1 and principal components of thigh muscle 1 were correlated with SREBP1 and PPARα, respectively (P < 0.05). In conclusion, with increasing age, FRS enhanced IMF deposition in breast muscle, and the same promotion in thigh muscle was because of NRS. The variation of fatty acids in muscles was uniform, and the change of single fatty acid was unable to distinguish NRS and FRS. However, as NRS downregulated SREBP1, ACADL and FABP3 in breast muscle and upregulated PPARα and ELOVL5 in thigh muscle, NRS could improve nutrient value and meat quality by increasing ƩMUFA, ƩMUFA/ƩSFA ratio, and important PUFA levels. Therefore, NRS was more recommended than FRS for Nonghua ducks during week 8 to 13 posthatching.

Genome-wide transcriptome profiling reveals the mechanisms underlying muscle group-specific phenotypic changes under different raising systems in ducks

Although a number of nongenetic factors have been reported to be able to modulate skeletal muscle phenotypes in meat-type birds, neither the underlying mechanisms nor the muscle group–specific phenotypic and molecular responses have been fully understood. In the present study, a total of 240 broiler ducks were used to compare the effects of floor raising system (FRS) and net raising system (NRS) on the physicochemical properties and global gene expression profiles of both breast and thigh muscles at the posthatching week 4 (W4), W8, and W13. Our results showed that compared with FRS, NRS generally induced higher pH, lower lightness (L∗) and yellowness (b∗), lower drip loss and cooking loss, and lower shear force in either breast or thigh muscles during early posthatching stages but subsequently showed less pronounced or even reverse effects. Meanwhile, it was observed that the raising system differently changed the myofiber characteristics depending on the muscle group and the developmental stage. Genome-wide transcriptome analysis showed that compared with FRS, NRS induced the most extensive gene expression changes in breast muscle (BM) at W4 but in thigh muscle (TM) at W13, suggesting the asynchronous molecular responses of BM and TM to the raising system and period. Most of differentially expressed genes in either BM or TM between NRS and FRS were enriched in the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes terms associated with regulation of muscle cellular functions, metabolic and contractile activities, and tissue remodeling, indicating similar molecular mechanisms principally responsible for the raising system-caused phenotypic changes in both muscle groups. Nevertheless, several crucial pathways (e.g., adipocytokine signaling, AGE-RAGE signaling, and apoptosis) and genes (e.g., ANO6, ACER2, UCP3, DTL, and TMEM120A) were tightly related to the muscle group–specific adaptive remodeling on different raising systems. These data could not only contribute to a better understanding of the molecular mechanisms behind meat quality but also provide novel insights into the molecular causes of the muscle group–specific adaptive remodeling in response to environmental stimuli.

Meat quality traits and fatty acid composition of breast muscles from ducks fed with yellow lupin

The protein sources in feed have a huge impact on good-quality and -quantity meat traits. Yellow lupin (YL) seeds have a similar level of protein as soybean meal (SBM). The most popular is SBM that is genetically modified (GMO). During this age, the consumer market requires non-GMO products. Yellow lupin used as a high-protein substitute for SBM in feed has an effect on the quality of meat from broiler ducks. The aim of the study was to analyse and compare meat quality traits in breast and leg muscles as well as fatty acid (FA) composition in breast muscles from ducks fed mixtures containing YL as an alternative to SBM. Two hundred 1-day-old Cherry Valley ducks were kept in pens on litter in two equal dietary groups, four replications with 25 birds per group. The control group (1) received balanced feed containing SBM. The treatment group (2) received balanced feed containing YL. The feed provided to both groups contained 55% of concentrate and 45% of wheat. Birds received feed and water ad libitum and were reared for 8 weeks. After that, 16 ducks (eight from each group) of BW close to the mean for the whole group were slaughtered. Plucked and gutted carcasses were analysed in a laboratory for quality parameters. Meat was analysed for pH, colour, water-holding capacity and drip loss. Samples of breast muscles were analysed for the content of cholesterol, collagen, intramuscular fat and FA composition. The proposed feed mixture containing YL had no impact on meat traits, content of muscles or fat in duck carcasses (P > 0.05). The values of lightness (L*) and yellowness (b*) and collagen content in breast muscles were significantly higher (P < 0.05) in group 2 (YL). A lower ability to retain water, that is, higher water-holding capacity (percentage of water lost from meat) (P < 0.05), was found for leg muscles from group 2 (YL). The content of C16:0, C18:0, C20:4 n-6, C22:4 n-6, C22:5 n-3, total content of saturated fatty acids (SFA), values of atherogenic index and thrombogenic index were significantly lower (P < 0.05) in group 2 (YL) than in group 1 (SBM). The content of C18:2 n-6 and the polyunsaturated fatty acids-to-SFA ratio (P/S) were significantly higher (P < 0.05) in ducks fed the diet with the inclusion of YL. Diets with YL could be proposed as a partial substitute for SBM in duck-rearing.

Effect of L-theanine on meat quality, muscle amino acid profiles, and antioxidant status of broilers

This study investigated the effect of L-theanine on carcass traits, meat quality, muscle antioxidant capacity, and amino acid (AA) profiles of broilers. Three hundred 1-day-old Ross 308 male broilers were randomly allotted to five groups with six replicates. Birds were fed the basal diet or basal diet with 300, 600, 900, or 1,500 mg/kg L-theanine for 42 consecutive days. The results showed that L-theanine quadratically increased dressing percentage, eviscerated percentage, and leg muscle yield (p < .05). Meanwhile, drip loss, cooking loss, shear force, L*_24h, and muscle lactate content decreased quadratically in response to dietary L-theanine supplementation (p < .05), while pH_24h and muscle glycogen content were quadratically improved by L-theanine (p < .05). Notably, the contents of muscle malondialdehyde and protein carbonyl, and the activities of muscle total antioxidant capacity, catalase, and glutathione peroxidase decreased quadratically in response to dietary L-theanine supplementation (p < .05), suggesting that the oxidative stress level of muscle was decreased quadratically. Moreover, L-theanine quadratically increased the concentrations of most of muscle essential AA, nonessential AA, and flavor AA (p < .05). In conclusion, L-theanine can be used as a valuable feed additive to modulate carcass traits, meat quality, muscle antioxidant status, and AA profiles of boilers, and its optimum addition level is 600 mg/kg based on the present study.

Influence of housing systems on duck behavior and welfare

Objective:

This experiment was conducted to assess the effects of the housing system on the welfare and growth performance of the Muscovy duck.

Materials and methods:

A total number of 48 Muscovy duck aged 3-week old were divided randomly into two groups (24 duck on each): deep litter system and cage system. Each group was subdivided into three replicates (8 birds on each) were identified with wing rings.

Results:

The study showed that feeding and drinking behaviors significantly increased (p < 0.05) in duck reared at the cage system. While there was no noticeable effect on lying and feather pecking, duck raised in the deep litter had better growth performance with a substantial difference, which achieve a higher feed conversion rate with lower feed efficiency. Physical conditions were significantly better at cage management. The level of stress indicating hormones indicating free Thyroxin was increased with the cage. Therefore, the litter system improves duck welfare and their performance.

Conclusion:

It is concluded that the duck managed under the litter system has more opportunities that facilitate the expression of more natural behavior, and thus improve their health and performance, as a result of improved feed conversion rate and feed efficiency.

1H NMR-based metabolomics study of breast meat from Pekin and Linwu duck of different ages and relation to meat quality

This study investigated the effects of breed and age on meat quality, and metabolite profiles of duck breast meat, and the relationship between changes in metabolite profiles and the meat quality. The meat quality and 1H nuclear magnetic resonance (NMR)-based metabolomics of breast meat from Pekin and Linwu ducks at 2 different ages (42 and 72d) was analyzed. The results showed that age exerted a greater effect on the observed meat quality traits of breast meat than breed, and its interaction (breed × age) effect on pH values and yellowness (b*) of duck breast meat was significant. Total of 32 metabolites were detected in breast meat of Pekin and Linwu duck. The difference of metabolite profiles in breast meat between Pekin and Linwu duck at 72 d was greater than that at 42 d, while the effects of age on metabolites of duck meat from both breeds were similar. Anserine, aspartate, and carnosine were the most relevant metabolites of duck breast meat quality, and nicotinamide in duck breast meat was negatively correlated with cooking loss. These results provide an overall perspective for bridging the gap between the breed and age on duck meat quality and metabolome, and improve the understanding of the relationship between metabolites and duck meat quality.

Influence of free-range days on growth performance, carcass traits, meat quality, lymphoid organ indices, and blood biochemistry of Wannan Yellow chickens

This study investigated the effects of free-range days on growth performance, carcass traits, meat quality, lymphoid organ indices, and blood biochemical parameters of Wannan Yellow chickens. A total of 1,000 one-day-old male Wannan Yellow chickens were reared to 56 D. At 56 D of age, 960 birds with similar body weight (BW) were randomly allocated to free-range treatment at 56, 70, 84, and 98 D of age (assigned to free-range treatment for 42, 28, 14, and 0 D, respectively); 6 replicates with 40 chickens per treatment. In the free-range system, chickens were reared in indoor floor pens with an outdoor free-range paddock measuring 4 × 7 m (28 m2, 1.5 birds/m2). Results showed that BW of birds decreased significantly in the first 2 wk after birds were assigned to free-range treatment compared with those in the conventional treatment (P < 0.05). Average daily gain (ADG) and average daily feed intake (ADFI) decreased significantly (P < 0.05) for chickens assigned to free-range treatment from 56 to 70 D of age, while feed conversion ratio increased significantly (P < 0.05). Breast yield increased linearly with increasing free-range days (P < 0.05), whereas leg and foot yields decreased linearly (P < 0.05). Drip loss and L* value of thigh muscle decreased linearly with increasing free-range days (P < 0.05), while shear force improved linearly (P < 0.05). Additionally, the absolute thymus weight and thymus to BW ratio showed significant increasing and then decreasing quadratic responses to increasing free-range days (P < 0.05). Furthermore, serum glucose, total protein, cholesterol, and triglyceride content declined linearly, while high-density lipoprotein cholesterol (HDL-C) content increased linearly with increasing free-range days (P < 0.05). In conclusion, increasing free-range days had positive effects on breast yield, shear force, thymus weight, and HDL-C content, but negatively affected leg yield, foot yield, drip loss, L* value of thigh muscle, glucose, total protein, cholesterol, and triglyceride levels of Wannan Yellow chickens.

Research Note: Effects of the rearing method and stocking density on carcass traits and proximate composition of meat in small-sized meat ducks

The present study was conducted to evaluate the effects of different rearing methods and stocking densities on carcass yield and proximate composition of meat in small-sized meat ducks. A total of 555 one-day-old birds were randomly allocated to six treatment groups (three replicates per treatment, sex ratio 1/1) with a 2 × 3 factorial arrangement of two rearing methods (reared in cage or net) and three stocking densities (5 [low], 7 [medium], or 9 [high] birds/m²) until day 70. Five male and five female birds from each replicate were randomly selected and processed to determine the carcass yield. Proximate composition was determined by proximate analysis using the breast and thigh muscles. There was no interaction effect between the rearing method and stocking density on carcass yield. The rearing method affected the thigh muscle rate, which was higher in the cage groups (P < 0.05). The final BW and abdominal fat rate decreased with increasing density (P < 0.05), whereas the thigh muscle rate increased (P < 0.05). There were significant interaction effects (P < 0.05) between the rearing method and stocking density on the content of protein, fat, and collagen. The content of fat and moisture was greater and lower, respectively, in the cage groups (P < 0.05). The content of moisture, fat, and collagen with a medium density was higher (P < 0.05). In addition, the content of protein and fat was lower in the ducks fed in nets at low and high densities (P < 0.05), respectively; the collagen content of breast and thigh muscle was lower in the ducks fed in cages and nets, respectively, at a low density (P < 0.05). Our findings provide valuable insights into the single and interactive effects of the rearing method and stocking density on duck slaughter performance and proximate composition of meat. The results indicate that a rearing system with a cage pattern and a medium density is better than other arrangements for small-sized meat ducks.

Comparison of slaughter performance, meat traits, serum lipid parameters and fat tissue between Chaohu ducks with high- and low-intramuscular fat content

This study was conducted to investigate the effect of intramuscular fat (IMF) on carcass traits of Chaohu ducks. Two-hundred-forty ducks were separated by sex and raised in separate pens. Slaughter performance, meat quality, and serum lipid parameters were identified. Based on IMF, samples were divided into males with high IMF (CHM) or low IMF (CLM) and females with high IMF (CHF) or low IMF (CLF). There were significant differences in the living body weight, abdominal fat ratio (%), shear force, IMF, total cholesterol (TC), high-density lipoprotein (HDL) and low-density lipoprotein (LDL) content between female and male ducks. In addition, compared with the CLM group, the shear force (p = 0.001) was significantly greater but the lightness (p = 0.006) was lower in the CHM group. TC, HDL and LDL content were also significantly higher (p = 0.033, 0.027 and 0.012, respectively) in the CHM group. The butcher ratio (0.028), eviscerating rate (0.039) and breast meat ratio (0.028) in the CHF group was significantly lower than that in CLF group, while these parameters showed no difference between CHM and CLM. In conclusion, IMF had a significantly positive correlation with subcutaneous fat and abdominal fat and was also positively correlated with TC, HDL and LDL in Chaohu ducks.

Effects of rearing systems on growth performance, carcass yield, meat quality, lymphoid organ indices, and serum biochemistry of Wannan Yellow chickens

This study was conducted to investigate the effects of free-range system (FRS) and conventional cage-rearing system (CRS) on growth performance, carcass yield, meat quality, lymphoid organ indices, and serum biochemistry of Wannan Yellow chickens. At 56 days of age, a total of 640 male chickens were randomly allocated to FRS and CRS groups, each of which included 4 replicates with 80 chickens in each replicate. The experiment lasted from 56 to 112 days of age. The results showed that CRS chickens exhibited better final body weight, average daily feed intake, average daily gain, and feed conversion ratio, whereas FRS chickens showed better breast and leg yields, shear force, meat color, lower drip loss, and decreased abdominal fat deposition. Moreover, the absolute thymus weight and thymus to body weight ratio of FRS birds were significantly higher than those of CRS birds (p < 0.05). Additionally, FRS chickens had significantly reduced glucose, total protein, triglyceride, and cholesterol contents, but enhanced levels of high-density lipoprotein cholesterol (p < 0.05). In conclusion, the FRS has advantages in breast and leg yields, meat quality, and some serum biochemical parameters of Wannan Yellow chickens, whereas it has negative effects on growth performance.

Effect of l-theanine on the growth performance, immune function, and jejunum morphology and antioxidant status of ducks

l-theanine is a unique nonproteinogenic amino acid found in tea, and has recently received considerable attention because of its various biological activities. However, there is no available research report on the use of l-theanine as a feed additive in ducks. This study was conducted to investigate the potential benefits and appropriate dosages of l-theanine on the growth performance, immune function, serum biochemical parameters, and jejunum morphology and antioxidant capacity of ducks. A total of 600 1-day-old Chaohu ducks were randomly allocated into five dietary treatment groups supplemented with 0 (control group), 300, 600, 900 and 1500 mg/kg of l-theanine. Each group included five replicates of 24 birds each. Body weight at day 28 was increased (P&lt;0.05) by l-theanine. From days 15 to 28, l-theanine elevated cumulative BW gain (BWG) and cumulative feed intake (FI), and decreased feed to gain ratio. From days 1 to 28, l-theanine elevated (P&lt;0.05) cumulative BWG and cumulative FI. l-theanine elevated (P&lt;0.05) the relative weight of bursa of Fabricus (day 14), thymus (day 14), spleen (day 28) and liver (day 28). On day 28, l-theanine decreased (P&lt;0.05) serum glucose, uric acid, triacylglycerol, total cholesterol, low-density lipoprotein cholesterol, insulin, interleukin-2 (IL-2) and IL-6 contents, and elevated (P&lt;0.05) serum total protein, globulin (GLB), immune globulin A (IgA) and IgG contents, but only serum insulin, interferon-γ, tumor necrosis factor-α and IL-6 contents was decreased (P&lt;0.05) and serum GLB and IgM content was elevated (P&lt;0.05) by l-theanine on day 14. On day 14, l-theanine decreased (P&lt;0.05) jejunum crypt depth, and elevated (P&lt;0.05) jejunum villus height, villus height to crypt depth ratio (V/C), goblet cell number and total superoxide dismutase (T-SOD) activity. On day 28, l-theanine decreased (P&lt;0.05) jejunum malondialdehyde content, and elevated (P&lt;0.05) jejunum villus height, V/C, goblet cell number, and T-SOD, catalase and glutathione peroxidase activities. l-theanine levels caused quadratic effect on the growth performance, relative organ weight, serum parameters, jejunum morphology and antioxidant capacity. In conclusion, l-theanine can be used as a promising feed additive for ducks, and its optimal supplementation level was 600 to 900 mg/kg based on the current experimental condition.