This study aimed to establish the optimal dietary zinc requirement of Chinese yellow-feathered Lingnan broiler breeders. A total of 576 breeder hens aged 58 weeks were randomly assigned to six treatments, each with 6 replicates of 16 birds (n = 96/treatment). The hens were fed either a basal diet (22.81 mg/kg Zn) or the same basal diet supplemented with additional 24, 48, 72, 96, and 120 mg Zn/kg up to 65 weeks of age. Compared to the results of birds fed the basal diet (22.81 mg Zn/kg), the dietary supplementation with additional Zn (mg/kg) showed higher egg laying rate (at 48–120 mg), EM (at 96 mg/kg), yolk Zn content (at 24–120 mg/kg), fertility (at 48–120 mg/kg), hatchability (at 48–96 mg/kg), tibial breaking strength (at 24–48 mg/kg), tibial ash content (at 48 mg/kg), serum CuZnSOD activity (at 72 mg/kg) and T-AOC (at 48 mg/kg), and ovarian CuZnSOD and GSH-Px activities (at 96–120 mg/kg), and lower FCR (at 96 mg/kg). The regression model showed that the optimal supplemental Zn for maximal egg laying rate, yolk Zn content, fertility, and hatchability of Chinese yellow-feathered broiler breeders aged 58 to 65 weeks were 71.09, 92.34, 94.44 and 98.65 mg/kg diet, respectively.

A dose-response study was conducted to investigate the metabolizable energy (ME) requirement for Lingnan chickens from 9 to 15 weeks of age. One thousand two hundred 8-week-old slow-growing yellow-feathered male chickens were allotted to five dietary ME levels (2805, 2897, 2997, 3095 and 3236 kcal/kg). The results revealed that the daily metabolizable energy intake increased (p 0.01), whereas the feed intake and feed:gain ratio decreased linearly (p 0.01) with the increment in dietary ME level. The final body weight and daily gain of the highest ME treatment tended (p > 0.05) to be greater than those obtained with the lower ME levels. The fat content in breast muscle showed a quadratic response (p 0.05) to the increase in dietary energy level. The shear force values of breast muscle in the 2897, 3095 and 3236 kcal/kg treatments were lower (p 0.05) than those of the 2997 kcal/kg treatment. In conclusion, among the tested ME levels, 3095 kcal/kg was adequate for feed intake, shear force, and plasma uric acid, and 3236 kcal/kg tended to increase the body weight, body gain, and feed conversion ratio of Lingnan males between 9 and 15 weeks of age; further studies are still required for testing higher levels

The fatty acid composition of chicken’s meat is largely influenced by dietary lipids, which are often used as supplements to increase dietary caloric density. The underlying key metabolites and pathways influenced by dietary oils remain poorly known in chickens. The objective of this study was to explore the underlying metabolic mechanisms of how diets supplemented with mixed or a single oil with distinct fatty acid composition influence the fatty acid profile in breast muscle of Qingyuan chickens. Birds were fed a corn-soybean meal diet supplemented with either soybean oil (control, CON) or equal amounts of mixed edible oils (MEO; soybean oil : lard : fish oil : coconut oil = 1 : 1 : 0.5 : 0.5) from 1 to 120 days of age. Growth performance and fatty acid composition of muscle lipids were analysed. LC-MS was applied to investigate the effects of CON v. MEO diets on lipid-related metabolites in the muscle of chickens at day 120. Compared with the CON diet, chickens fed the MEO diet had a lower feed conversion ratio (P 0.05), higher proportions of lauric acid (C12:0), myristic acid (C14:0), palmitoleic acid (C16:1n-7), oleic acid (C18:1n-9), EPA (C20:5n-3) and DHA (C22:6n-3), and a lower linoleic acid (C18:2n-6) content in breast muscle (P 0.05). Muscle metabolome profiling showed that the most differentially abundant metabolites are phospholipids, including phosphatidylcholines (PC) and phosphatidylethanolamines (PE), which enriched the glycerophospholipid metabolism (P 0.05). These key differentially abundant metabolites – PC (14:0/20:4), PC (18:1/14:1), PC (18:0/14:1), PC (18:0/18:4), PC (20:0/18:4), PE (22:0/P-16:0), PE (24:0/20:5), PE (22:2/P-18:1), PE (24:0/18:4) – were closely associated with the contents of C12:0, C14:0, DHA and C18:2n-6 in muscle lipids (P 0.05). The content of glutathione metabolite was higher with MEO than CON diet (P 0.05). Based on these results, it can be concluded that the diet supplemented with MEO reduced the feed conversion ratio, enriched the content of n-3 fatty acids and modified the related metabolites (including PC, PE and glutathione) in breast muscle of chickens.

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.

Pre-slaughter transport exerts negative effects on broilers’ welfare, meat yield, and meat quality, but little is known about the effect of transport on medium-growing broiler chickens. This study aimed at evaluating the effects of different durations of transport (0, 0.5, 1, 2, and 3 h) on stress biomarkers and meat quality of medium-growing Yellow-feathered broiler chickens. One hundred and eighty Chinese Yellow-feathered broilers aged 75 days (marketing age), of 2.02 kg average BW, were allotted into five groups; each group contained six replicates (six birds/replicate (crate)). Each crate with dimensions 74 × 55 × 27 cm (length × width × height) was loaded with six birds, that is, 30 kg live BW/m2 crate. The tested transport durations increased BW loss (linear, P 0.01), plasma concentrations of ACTH (linear, P 0.10), cortisol and corticosterone (quadratic, P 0.05), and activity of glutathione peroxidase (linear, P 0.05), whereas plasma glucose was not affected. In breast muscle, contents of glycogen, lactic acid, malondialdehyde, and reduced glutathione were not affected (P > 0.05), but total antioxidant capacity decreased (linear, P 0.01). The drip loss of breast muscle increased (linear, P 0.01), whereas shear force, pH at 24 h postmortem, and breast meat color lightness (L*), redness (a*), and yellowness (b*) scores were not affected. In conclusion, the tested transport durations (from 0.5 to 3 h) increased BW loss and some plasma stress biomarkers in 75-day-old Yellow-feathered broiler chickens, but the effect on meat quality attributes was minor.

Nowadays, there is much legislation in the world devoted to restrict the use of synthetic antibiotics in the poultry industry, which could reduce performance rate and production profits. Various phyto-biotic growth promoters have been proposed to serve as antibiotic alternatives with emphasis on plant extracts and essential oils. This study was conducted to assess the impacts of using the oregano essential oil (OEO) (comprised of 5% thymol and 65% carvacrol) and Enviva essential oil (EEO) (4.5% cinnamaldehyde and 13.5% thymol) as phytobiotic feed additives (PFA) on growth performance, cecal microbiota and serum biochemicals of growing ducks. In total, 800 11-day-old ducklings, housed in 20 floor pens, were allotted randomly into five dietary treatments: (i) A basal diet (BD) (control), (ii.) BD+50 mg EEO/kg, (iii.) BD+100 mg EEO/kg, (iv.) BD+150 mg OEO/kg and (v.) BD+300 mg OEO/kg diet. The growth performance traits were studied between 11 and 42 days of age. At the experiment end, 40 ducks were slaughtered (eight/ treatment) and cecal digesta and blood samples were collected to estimate the cecal bacterial populations and serum blood biochemicals. The results indicated that the tested levels of OEO and EEO did not display any significant effect (P>0.05) on the duck’s final BW, BW gain, growth rate, feed intake, feed conversion ratio or survivability rate. Besides, the different levels of EEO and OEO decreased the cecal populations of Coliforms (P0.01), total aerobes (P0.01) and lactose-negative Enterobacteria (P0.05) in comparison with those of the control group. Finally, the tested EEO and OEO levels did not show any significant effect on the serum variables; in terms of total protein, albumin, globulin, total cholesterol, triglycerides, alanine aminotransferase and aspartate aminotransferase. In conclusion, the antimicrobial effect of the OEO and EEO against the cecal microbiota has been proven, while they did not display significant effects on the growth performance or blood variables of growing ducks.

The hydroponic fodder industry has been extensively advertised and has a renewed interest among scientists and livestock producers. This study was designed to evaluate the nutritional impacts of hydroponically sprouted barley (HSB) as a feed supplement on egg production, egg quality, reproductive performance, and blood analyses of laying Japanese quails. Seventy-two laying Japanese quails, housed in twelve battery cages, each of six birds (two males + four females), were assigned randomly to three feeding treatments: (i) a commercial diet provided ad libitum (control), (ii) ad libitum diet plus fresh HSB (ad lib + HSB), and (iii) a restricted feed amount of the same diet (15% lower than that of the control), plus fresh HSB (RST + HSB). The data collection continued for 11 weeks. The fresh-8-days HSB contained 163.8 g/kg of dry matter, with crude protein and aNDFom contents of 230.3 g/kg DM, and 267 g/kg DM. Compared to the control diet, the ad lib + HSB had a higher (P 0.05) egg laying rate (0.963 vs. 0.888), fertility (0.921 vs. 0.886), number of hatched chicks, relative weights of the gizzard and testis, and longer oviducts. On the other hand, the RST+ HSB treatment maintained a similar egg laying rate and fertility to those of the controls (P > 0.05), but with a lower daily egg mass (10.84 vs. 11.29 g egg/female/day) and hatchability (0.582 vs. 0.671). The egg quality variables, activity of blood total antioxidant capacity, and plasma contents of cholesterol, free fatty acids, total protein and globulin were not affected by the treatments. To conclude, the feed restriction (-15% of feed amount) did not increase the HSB intake, and the ingested HSB amount did not completely compensate the reduction in nutrient intake, which led to reduced daily egg mass, fertility and hatchability. Providing the ad libitum fed laying Japanese quail with fresh HSB significantly increased the egg laying rate, relative weights of gizzard and testis, fertility and number of hatched chicks/female, but did not affect egg quality indices or blood analysis.

The hydroponic fodder industry has been extensively advertised and has a renewed interest among scientists and livestock producers. This study was designed to evaluate the nutritional impacts of hydroponically sprouted barley (HSB) as a feed supplement on egg production, egg quality, reproductive performance, and blood analyses of laying Japanese quails. Seventy-two laying Japanese quails, housed in twelve battery cages, each of six birds (two males + four females), were assigned randomly to three feeding treatments: (i) a commercial diet provided ad libitum (control), (ii) ad libitum diet plus fresh HSB (ad lib + HSB), and (iii) a restricted feed amount of the same diet (15% lower than that of the control), plus fresh HSB (RST + HSB). The data collection continued for 11 weeks. The fresh-8-days HSB contained 163.8 g/kg of dry matter, with crude protein and aNDFom contents of 230.3 g/kg DM, and 267 g/kg DM. Compared to the control diet, the ad lib + HSB had a higher (P 0.05) egg laying rate (0.963 vs. 0.888), fertility (0.921 vs. 0.886), number of hatched chicks, relative weights of the gizzard and testis, and longer oviducts. On the other hand, the RST+ HSB treatment maintained a similar egg laying rate and fertility to those of the controls (P > 0.05), but with a lower daily egg mass (10.84 vs. 11.29 g egg/female/day) and hatchability (0.582 vs. 0.671). The egg quality variables, activity of blood total antioxidant capacity, and plasma contents of cholesterol, free fatty acids, total protein and globulin were not affected by the treatments. To conclude, the feed restriction (-15% of feed amount) did not increase the HSB intake, and the ingested HSB amount did not completely compensate the reduction in nutrient intake, which led to reduced daily egg mass, fertility and hatchability. Providing the ad libitum fed laying Japanese quail with fresh HSB significantly increased the egg laying rate, relative weights of gizzard and testis, fertility and number of hatched chicks/female, but did not affect egg quality indices or blood analysis.

The hydroponic fodder industry has been extensively advertised and has a renewed interest among scientists and livestock producers. This study was designed to evaluate the nutritional impacts of hydroponically sprouted barley (HSB) as a feed supplement on egg production, egg quality, reproductive performance, and blood analyses of laying Japanese quails. Seventy-two laying Japanese quails, housed in twelve battery cages, each of six birds (two males + four females), were assigned randomly to three feeding treatments: (i) a commercial diet provided ad libitum (control), (ii) ad libitum diet plus fresh HSB (ad lib + HSB), and (iii) a restricted feed amount of the same diet (15% lower than that of the control), plus fresh HSB (RST + HSB). The data collection continued for 11 weeks. The fresh-8-days HSB contained 163.8 g/kg of dry matter, with crude protein and aNDFom contents of 230.3 g/kg DM, and 267 g/kg DM. Compared to the control diet, the ad lib + HSB had a higher (P 0.05) egg laying rate (0.963 vs. 0.888), fertility (0.921 vs. 0.886), number of hatched chicks, relative weights of the gizzard and testis, and longer oviducts. On the other hand, the RST+ HSB treatment maintained a similar egg laying rate and fertility to those of the controls (P > 0.05), but with a lower daily egg mass (10.84 vs. 11.29 g egg/female/day) and hatchability (0.582 vs. 0.671). The egg quality variables, activity of blood total antioxidant capacity, and plasma contents of cholesterol, free fatty acids, total protein and globulin were not affected by the treatments. To conclude, the feed restriction (-15% of feed amount) did not increase the HSB intake, and the ingested HSB amount did not completely compensate the reduction in nutrient intake, which led to reduced daily egg mass, fertility and hatchability. Providing the ad libitum fed laying Japanese quail with fresh HSB significantly increased the egg laying rate, relative weights of gizzard and testis, fertility and number of hatched chicks/female, but did not affect egg quality indices or blood analysis.

The hydroponic fodder industry has been extensively advertised and has a renewed interest among scientists and livestock producers. This study was designed to evaluate the nutritional impacts of hydroponically sprouted barley (HSB) as a feed supplement on egg production, egg quality, reproductive performance, and blood analyses of laying Japanese quails. Seventy-two laying Japanese quails, housed in twelve battery cages, each of six birds (two males + four females), were assigned randomly to three feeding treatments: (i) a commercial diet provided ad libitum (control), (ii) ad libitum diet plus fresh HSB (ad lib + HSB), and (iii) a restricted feed amount of the same diet (15% lower than that of the control), plus fresh HSB (RST + HSB). The data collection continued for 11 weeks. The fresh-8-days HSB contained 163.8 g/kg of dry matter, with crude protein and aNDFom contents of 230.3 g/kg DM, and 267 g/kg DM. Compared to the control diet, the ad lib + HSB had a higher (P 0.05) egg laying rate (0.963 vs. 0.888), fertility (0.921 vs. 0.886), number of hatched chicks, relative weights of the gizzard and testis, and longer oviducts. On the other hand, the RST+ HSB treatment maintained a similar egg laying rate and fertility to those of the controls (P > 0.05), but with a lower daily egg mass (10.84 vs. 11.29 g egg/female/day) and hatchability (0.582 vs. 0.671). The egg quality variables, activity of blood total antioxidant capacity, and plasma contents of cholesterol, free fatty acids, total protein and globulin were not affected by the treatments. To conclude, the feed restriction (-15% of feed amount) did not increase the HSB intake, and the ingested HSB amount did not completely compensate the reduction in nutrient intake, which led to reduced daily egg mass, fertility and hatchability. Providing the ad libitum fed laying Japanese quail with fresh HSB significantly increased the egg laying rate, relative weights of gizzard and testis, fertility and number of hatched chicks/female, but did not affect egg quality indices or blood analysis.