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The present study determined the effects of in ovo feeding (IOF) of N-acetyl-L-glutamate (NAG) on early intestinal development and growth performance of broilers. A total of 702 fertile broiler eggs were randomly divided into 3 treatments: 1) non-punctured control group, 2) saline-injected control group, and 3) NAG solution–injected group (1.5 mg/egg). At 17.5 D of incubation, 300 μL of each solution was injected into each egg of injected groups. Results indicated that the hatchability and healthy chicken rate were not affected by NAG injection (P > 0.05). Chicks from NAG solution–injected group had significantly decreased average daily feed intake and feed conversion ratio during 1–14 D than those in the non-punctured control group (P

This study was conducted to determine the standardized ileal digestible amino acids (SID AA) and nitrogen-corrected apparent metabolizable energy (AMEn) contents of 6 wheats from different origins in China and incidentally to investigate the effects of exogenous xylanase addition on SID AA and AMEn determination in broiler chicks. A total of 480 chicks were divided into 48 cages of 10 birds each balanced for body weight and fed 8 types of diets in a completely randomized design (6 replicated cages per diet) from 21 to 26 d of age. The individual wheat constituted the only source of crude protein in a semi-purified experimental diet. A nitrogen-free diet was designed to estimate basal endogenous AA loss and determine the SID AA. Titanium oxide (0.3%) was used as an indigestibility marker, and nutrient digestibility and retention were determined by the substitution method. From day 24 to 26, excreta samples were collected for AMEn determination. On day 26, the birds were euthanized, and ileum contents were obtained for AA digestibility determination. Wheat from Gansu had greater (P

This study was aimed to probe broiler responses to the maintenance of adequate level of glycine plus serine in low crude protein (CP) diets by glycine (Gly) addition from 8 to 42 days of age. A total of 1152 7-d-old birds were divided into 8 groups and fed with one of the following diets: (I) normal CP diet; (II, III vIV V) diets with 1.5%, 3%, 4.5% and 6% points less CP than normal diet, respectively; (VI, VII, VIII) diets with 3%, 4.5% and 6% points reduced CP than the normal CP diet, respectively, and added with Gly to achieve 2.32% total Gly + Ser. Each treatment was replicated with 12 cages. Results showed that dietary CP reduction by 3% or higher compromised (p .05) abdominal fat percentage of birds fed the diet containing 4.5% points less CP as compared with birds fed the normal-CP diet. Comparatively, Gly fortification in the diet with a 6% CP reduction resulted in breast muscle yield, serum UN content on d 21 and albumin content on d 42 comparable to (p > .05) those in normal-CP group. Collectively, the absence of Gly addition allowed dietary CP reduction by no more than 3% to obtain normal performance and carcase traits of broilers. Gly fortification in the diet with a 3% CP reduction induced no improvements in growth performance and carcase traits of broilers. However, maintain a level of 2.32% total Gly + Ser via Gly fortification enabled a reduction of dietary CP by 4.5% without deteriorating the accumulative growth performance and carcase traits of broilers.Highlights Gly addition that provides 2.32% total Gly + Ser allows dietary CP reduction of 4.5% without compromising the accumulative growth performance and carcase traits of broilers. Maintaining 2.32% total Gly + Ser via Gly fortification could not completely overcome the depression of growth performance in broilers fed the diet with a 6% CP reduction.

A study was conducted to invesstigate the housefly maggot meal (HMM) as an alternative protein source to replace the soybean meal in broiler chick's diet. A total of 720 1-day-old male broiler chicks were divided into three groups and fed diets formulated with HMM to replace soybean meal at the rate of 0%, 4% and 8%. The study lasted for 42 days in two phases. Results showed that HMM addition did not markedly affect body weight, average daily body weight gain and average daily feed intake of the broiler chicks. Feed conversion ratio increased linearly (1-21 days) in starter or quadratically (22-42 days) in the grower phase. HMM non-significantly increased the feed intake and body weight during the grower phase. Slight changes were observed for decrease of blood biochemical indices in the platelets (day 21), and alkaline phosphatase and lysozyme (day 42), and increase for red blood cells, packed cell volume, total protein and uric acid on day 42; however, the fluctuations were within the physiological range. Non-significant effects were observed for carcass composition and meat quality, except that HMM numerically reduced the shear force of breast muscle (linear, p = .058). These results are the strong evidence that HMM can be used as an alternative protein source at 8% in broiler chick's diet without any adverse effect on chick's performance.

Bacillus subtilis (B. subtilis) as in-feed probiotics is a potential alternative for antibiotic growth promoters (AGP) in the poultry industry. The current study investigated the effects of B. subtilis on the performance, immunity, gut microbiota, and intestinal barrier function of broiler chickens. A 42-day feeding trial was conducted with a total of 600 1-day-old Arbor Acres broilers with similar initial body weight, which was randomly divided into one of five dietary treatments: the basal diet (Ctrl), Ctrl + virginiamycin (AGP), Ctrl + B. subtilis A (BSA), Ctrl + B. subtilis B (BSB), and Ctrl + B. subtilis A + B (1:1, BSAB). The results showed significantly increased average daily gain in a step-wise manner from the control, B. subtilis, and to the AGP groups. The mortality rate of the B. subtilis group was significantly lower than the AGP group. The concentrations of serum immunoglobulin (Ig) G (IgG), IgA, and IgM in the B. subtilis and AGP groups were higher than the control group, and the B. subtilis groups had the highest content of serum lysozyme and relative weight of thymus. Dietary B. subtilis increased the relative length of ileum and the relative weight of jejunum compared with the AGP group. The villus height (V), crypt depth (C), V/C, and intestinal wall thickness of the jejunum in the B. subtilis and AGP groups were increased relative to the control group. Dietary B. subtilis increased the messenger RNA (mRNA) expression of ZO-1, Occludin, and Claudin-1, the same as AGP. The contents of lactic acid, succinic acid, and butyric acid in the ileum and cecum were increased by dietary B. subtilis. Dietary B. subtilis significantly increased the lactobacillus and bifidobacteria in the ileum and cecum and decreased the coliforms and Clostridium perfringens in the cecum. The improved performance and decreased mortality rate observed in the feeding trial could be accrued to the positive effects of B. subtilis on the immune response capacity, gut health, and gut microflora balance, and the combination of two strains showed additional benefits on the intestinal morphology and tight junction protein expressions. Therefore, it can be concluded that dietary B. subtilis A and B could be used as alternatives to synthetic antibiotics in the promotion of gut health and productivity index in broiler production.

The current study investigated the effect of dietary l-histidine and beta-alanine supplementation on growth performance, meat quality, carnosine content, and gene expression of carnosine-related enzymes in broilers. A two-factor design was adopted in this study. A total of 640 1-day-old male broilers were assigned to eight treatments with factorial arrangement containing four levels of l-histidine (0, 650, 1300, or 1950 mg/kg) and two levels of beta-alanine (0 or 1200 mg/kg) supplementation, 0 mg/kg histidine and/or 0 mg/kg were treated as control groups. Each treatment including eight replicates with 10 birds each and the feeding trial lasted for 42 days. Dietary supplementation with l-histidine and beta-alanine did not affect average daily gain (ADG), average daily feed intake (ADFI), and feed conversion ratio (FCR) of broilers during the grower (22–42 days) and the entire phase (1–42 days), compared with the control group (p &gt, 0.05). The only exception was a significantly reduced ADG in the 1950 mg/kg l-histidine group in the starter period (1–21 days, p &lt, 0.05). l-Histidine at 1950 mg/kg significantly decreased redness (a*) and yellowness (b*) values of the meat at 45 min postmortem (p &lt, 0.05), whereas it increased b* value and pH in breast muscle at 24 h postmortem. Moreover, dietary supplementation with beta-alanine alone or combination with l-histidine significantly increased ΔpH in breast muscle (p &lt, 0.01). Dietary l-histidine markedly increased total superoxide dismutase activity and total antioxidant capacity (T-AOC) both in breast muscle (p &lt, 0.01) and in plasma (p &lt, 0.01), and it decreased malondialdehyde (MDA) concentration in breast muscle (p &lt, 0.01). Dietary addition of beta-alanine, alone or combination, significantly increased T-AOC in breast muscle (p &lt, 0.01) and markedly decreased MDA content both in breast muscle and in plasma (p &lt, 0.01). Addition of l-histidine and beta-alanine significantly increased muscle peptide (carnosine and anserine) content (p &lt, 0.05) and upregulated the expression of carnosine synthase, transporter of carnosine/ l-histidine, and l-histidine decarboxylase genes (p &lt, 0.05), with greater change occurring in the combination group of 1300 mg/kg l-histidine and 1200 mg/kg beta-alanine. Overall, dietary l-histidine and beta-alanine could improve meat quality and antioxidant capacity, enhance the carnosine and anserine content, and upregulate the gene expression of carnosine synthesis-related enzymes in broilers.

This study was aimed to estimate the relative bioavailability (RBA) of l-methionine (l-Met) to dl-methionine (dl-Met) in broiler chickens from 1 to 21 d of age. A total of 1664 one-day-old broiler chicks were randomly divided into 13 groups with 8 replicates per group. The basal diet contained 60% of the NRC requirement for Met. Birds in treatment groups were fed the basal diet supplemented with graded levels of dl- or l-Met, resulting in the dietary content of Met at 75%, 80%, 85%, 90%, 95% and 100% of the NRC requirement, respectively. Results showed that there were linear increases (p

This study was aimed to explore the metabolomical mechanisms for the potentially ameliorative effect of cyst(e)ine (Cys) fortification on growth performance of broilers fed low crude protein (CP) diet. A total of 432 1-d-old broilers were randomly divided into 6 groups, each of which received one of the following diets: normal-CP diet (positive control, PC), low-CP diet (negative control, NC), NC diet fortified with 0.05%, 0.1%, 0.15% or 0.2% of Cys. Samples were collected on d 42. Results showed that increasing Cys fortification quadratically elevated (P 0.05) the accumulative growth performance and leg muscle yield of broilers fed NC diet, with 0.1% being the optimal dose. Thus, samples from PC, NC and NC plus 0.1% Cys (NCC) groups were selected for further analysis. Both dietary CP reduction and fortification of 0.1% Cys in NC diet caused complex changes (P 0.05) in serum amino acids and some other metabolites primarily involved in lipid metabolism. Multiple lipogenesis-related pathways were regulated (P 0.05) following Cys fortification in NC diet, which could at least partially interpret the benefit of Cys fortification in NC diet on broiler performance. In conclusion, fortifying low-CP diet with 0.1% Cys promoted the growth performance of broilers probably through modulating serum metabolite profile.

The current study was performed to determine the influence of amniotic injection of N-carbamylglutamate (NCG) on meat quality of pectoral muscle in broilers. A total of 792 alive broiler embryos at 17 d of incubation were assigned to three treatments randomly (non-injected control, saline-injected control, or NCG-injected treatment). The two injection treatments were an injection with 0.1 mL 0.85% aseptic saline alone or containing 2 mg NCG per egg at 17.5 d of incubation. After hatching, 72 healthy male chicks were selected from each treatment and housed in six pens for a 42 day feeding study. Pectoral muscles from six 42-day-old broilers were collected from each treatment group and were dissected for meat quality assays. The results showed that arginine contents in pectoral muscle in either free or hydrolytic form in the NCG group were higher than those in the non-injection control group (p &lt, 0.05). In comparison to the non-injection or saline-injection control groups, NCG injection resulted in a lower lactic acid content in pectoral muscle (p &lt, 0.05). Muscular antioxidant capacity in the NCG group was higher, as evidenced by the higher activity of catalase and glutathione peroxidase and lower content of malondialdehyde (p &lt, 0.05). In addition, the group of in ovo administration of NCG had decreased drip loss and increased crude fat content in pectoral muscle in comparison to those of either control group (p &lt, 0.05) and had enhanced crude protein content compared to that of the saline-injection control group (p &lt, 0.05). Briefly, these results indicate that amniotic administration of NCG in the late incubation phase increased the arginine content, improved the nutritional properties, enhanced the antioxidant capacity, and improved the meat quality in the pectoral muscle of broilers. Amniotic injection of NCG may serve as a novel approach to improving the meat quality of broilers.

Yellow mealworm meal (MWM) as a protein feedstuff in the broiler diet was investigated based on the growth performance, hematological characteristics, carcass, and meat quality of broiler chicks. A total of 700 one-day-old Ross 308 male broiler chicks were assigned to five dietary MWM treatments containing 0%, 2%, 4%, and 8% dried MWM or 10.48% fresh mealworm (corresponding to 4% dried MWM). For each treatment, there were seven pens with 20 chicks each. The nutritional profile of dried MWM is comparable to all conventional protein feedstuffs. MWM significantly increased BW and ADG (linear and quadratic, p &lt, 0.05), and FCR was best at 4% MWM inclusion level (quadratic, p &lt, 0.10) for broiler chicks during the starter phase. The predicted MWM levels for optimal starter BW and ADG were 4.13% and 3.84%. Hematological characteristics of broiler chicks fed on the MWM diet did not differ or showed small change within the physiological range. A fresh 10.48% mealworm diet significantly reduced the blood LZM for the grower. Broiler Chicks fed on fresh 10.48% mealworm had a significantly reduced abdominal fat percentage compared to the 4% dried MWM counterparts. MWM did not significantly affect meat quality. Taken together, MWM inclusion in broiler diet is acceptable as a protein feedstuff, and a 4% level could stimulate early growth in the starter phase.

Background Meat color and lipid peroxidation are important traits related to meat quality. CO2 concentration is a critical factor that can affect meat quality in the commercial use of gas stunning (GS). However, the effect and mechanism of CO2 stunning on meat color and lipid peroxidation during long-term storage remain poorly studied. We aimed to study the effects of GS methods, especially CO2 concentration, on meat color and meat lipid peroxidation in broilers during long-term storage at 4 °C and to explore the potential mechanism of meat color change via lipid peroxidation and the inner lipid peroxide scavenging system. Methods Eighteen broilers were sacrificed after exposure to one of the following gas mixtures for 90 s: 40% CO2 + 21% O2 + 39% N2 (G40%), 79% CO2 + 21% O2 (G79%), or no stunning (0% CO2, control). Meat color, serum variables, enzyme activities, and the gene expression of mitogen-activated protein kinase (MAPK), nuclear factor-erythroid 2-related factor 2 (Nrf2), glutathione S-transferase (GST) and superoxide dismutase (SOD) were determined. Results The concentrations of serum triiodothyronine (T3, P = 0.03) and the ratio of serum free triiodothyronine/free thyroxine (FT3/FT4, P

The objective of the current study was to investigate the effect of dietary β-alanine supplementation on growth performance, meat quality, antioxidant ability, carnosine content, and gene expression of carnosine-related enzymes in broiler chicks. We randomly assigned 540 1-day-old Arbor Acres broilers to 5 dietary treatments supplemented with 0 (control group), 250, 500, 1,000, or 2,000 mg/kg of β-alanine (mg β-alanine per kg feed). Each treatment included 6 replicates of 18 birds. The feeding trial lasted for 42 d. Dietary β-alanine supplementation linearly and quadratically increased the average daily gain (ADG) during the starting period (d 1 to 21, P = 0.02 and P = 0.002). The feed conversion ratio (FCR) decreased quadratically in response to dietary β-alanine supplementation during the starting and entire periods (P0.001 and P = 0.003, respectively). For the entire period, the predicted best FCR would be achieved when β-alanine was fed at a level of 1,100 mg/kg from quadratic regression. The concentrations of carnosine and β-alanine in breast muscle increased quadratically with dietary β-alanine supplementation (d 42, P0.001 and P = 0.001, respectively). The predicted dietary β-alanine level for highest breast carnosine content was 1,196 mg/kg. Dietary supplementation with β-alanine reduced the taurine concentrations in plasma (d 42, linear and quadratic, P 0.001). Breast muscle yield increased linearly and quadratically in response to dietary β-alanine addition (d 21, P = 0.017 and P = 0.007). Dietary supplementation with β-alanine quadratically reduced the shear force (P = 0.003), whereas a*45 min and a*24 h values increased quadratically in response to dietary β-alanine supplementation (d 42, P = 0.020 and P = 0.021, respectively). Dietary β-alanine addition quadratically enhanced the expression of carnosine synthase and taurine transporter mRNAs (P0.05). Overall, dietary β-alanine supplementation improved growth performance and carnosine content, ameliorated antioxidant capacity and meat quality, and upregulated the gene expression of carnosine synthesis-related enzymes in broiler chicks.

Objective The objective of the present study was to determine whether mango saponin (MS) could be used as a feed additive in broiler chicks by evaluating growth performance, carcass characteristics, meat quality, and plasma biochemical indices. Methods A total of 216 1-d-old Arbor Acres male broiler chicks were randomly assigned into three dietary treatments supplemented with 0 (control), 0.14% (MS 0.14%), or 0.28% (MS 0.28%) MS. Each treatment had six replicates (cages) with 12 chicks each. The feeding trial lasted for six weeks. Results Compared with the control, dietary supplemented with 0.14% or 0.28% MS increased average daily weight gain of chicks in the grower (22 to 42 d) and the whole (1 to 42 d) phases, and the final body weight of chicks on d 42 was higher in MS supplemented groups (p

A 6-week experiment was conducted to evaluate the effects of dietary oregano powder (OP) supplementation on the growth performance, antioxidant status and meat quality of broiler chicks. A total of 180 one day-old Arbour Acres broilers were randomly divided into 3 treatments with 6 replicates and 10 chicks per replicate. The chicks were fed with basal diet without (CTR), or with 20 mg/kg of virginiamycin (ATB), or with 150 mg/kg of OP. At 21 and 42 days of age, two birds from each cage were selected for sampling. Compared to the CTR group, the OP supplementation increased average daily gain and average daily feed intake during the grower period (p = .047 and .03, respectively) and the whole period (p = .04 and .02, respectively). The supplementation of ATB and OP did not affect the immune organ index of chicks. In addition, dietary OP reduced malondialdehyde content and increased total antioxidant activity (T-AOC) in the serum of chicks at 21 (p

Grape proanthocyanidins (GPCs) are a family of naturally derived polyphenols that have aroused interest in the poultry industry due to their versatile role in animal health. This study was conducted to investigate the potential benefits and appropriate dosages of GPCs on growth performance, jejunum morphology, plasma antioxidant capacity and the biochemical indices of broiler chicks. A total of 280 newly hatched male Cobb 500 broiler chicks were randomly allocated into four treatments of seven replicates each, and were fed a wheat-soybean meal-type diet with or without (control group), 7.5, 15 or 30 mg/kg of GPCs. Results show that dietary GPCs decrease the feed conversion ratio and average daily gain from day 21 to day 42, increase breast muscle yield by day 42 and improve jejunum morphology between day 21 and day 42. Chicks fed 7.5 and 15 mg/kg of GPCs show increased breast muscle yield and exhibit improved jejunum morphologies than birds in the control group. Dietary GPCs fed at a level of 15 mg/kg markedly increased total superoxide dismutase (T-SOD) activity between day 21 and day 42, whereas a supplement of GPCs at 7.5 mg/kg significantly increased T-SOD activity and decreased lipid peroxidation malondialdehyde content by day 42. A supplement of 30 mg/kg of GPCs has no effect on antioxidant status but adversely affects the blood biochemical indices, as evidenced by increased creatinine content, increased alkaline phosphatase by day 21 and increased alanine aminotransferase by day 42 in plasma. GPC levels caused quadratic effect on growth, jejunum morphology and plasma antioxidant capacity. The predicted optimal GPC levels for best plasma antioxidant capacity at 42 days was 13 to 15 mg/kg, for best feed efficiency during grower phase was 16 mg/kg, for best jejunum morphology at 42 days was 17 mg/kg. In conclusion, GPCs (fed at a level of 13 to 17 mg/kg) have the potential to be a promising feed additive for broiler chicks.

Dietary inclusion of probiotic Bacillus spp. beneficially affect the broiler chickens by balancing the properties of the indigenous microbiota causing better growth performance. The effects of three Bacillus spp. on the growth performance, intestinal morphology and the compositions of jejunal microflora were investigated in broiler chickens. A total of 480 1-day-old male Arbor Acres broilers were randomly divided into four groups. All groups had six replicates and 20 birds were included in each replicate. The control birds were fed with a corn-soybean basal diet, while three treatment diets were supplemented with Bacillus coagulans TBC169, B. subtilis PB6, and B. subtilis DSM32315 with a dosage of 1 × 109 cfu/kg, respectively. The experiment lasted for 42 days. The compositions and diversity of jejunal microflora were analyzed by MiSeq high-throughput sequencing. The B. coagulans TBC169 group showed marked improvements of growth performance, nutrient digestibility and intestinal morphology compared with the other B. subtilis treatments. B. coagulans TBC169 supplementation improved the average body weight (BW), average daily weight gain (ADG), total tract apparent digestibility of crude protein and gross energy (GE), and reduced feed conversion rate (FCR) compared with the control group (P < 0.05). The villus height to crypt depth ratio (VH/CD) of jejunum and duodenum was increased in the birds fed with B. coagulans TBC169 compared with the control group (P < 0.05). However, two B. subtilis treatments presented more positive variation of the jejunum microflora of chickens than that in the B. coagulans TBC169 group. B. subtilis PB6 and B. subtilis DSM32315 treatments improved the diversity of jejunal microbiota on day 21 compared with the control (P < 0.05), while which were decreased on day 42 (P < 0.05). The supplementation with B. coagulans TBC169 significantly improved the proportion of Firmicutes, otherwise two B. subtilis significantly improved the proportion of Proteobacteria, Bacteroidetes, Actinobacteria, and Acidobacteria at the phylum level during starter phase and decreased the proportion of Bacteroidetes during growing phase compared with the control. The supplementation with B.subtilis DSM32315 significantly improved the proportion of Clostridiales during starter phase, whereas two B. subtilis significantly improved the proportion of Pseudomonas, Burkholderia, Prevotella, DA101 during growing phase at the genus level compared with the control. In conclusion, the dietary supplementation with probiotic Bacillus spp. strains improved body weight and intestinal morphology in broiler chickens, which might be associated with the gut microbiota.

Dietary inclusion of probiotic Bacillus spp. beneficially affect the broiler chickens by balancing the properties of the indigenous microbiota causing better growth performance. The effects of three Bacillus spp. on the growth performance, intestinal morphology and the compositions of jejunal microflora were investigated in broiler chickens. A total of 480 1-day-old male Arbor Acres broilers were randomly divided into four groups. All groups had six replicates and 20 birds were included in each replicate. The control birds were fed with a corn-soybean basal diet, while three treatment diets were supplemented with Bacillus coagulans TBC169, B. subtilis PB6, and B. subtilis DSM32315 with a dosage of 1 × 109 cfu/kg, respectively. The experiment lasted for 42 days. The compositions and diversity of jejunal microflora were analyzed by MiSeq high-throughput sequencing. The B. coagulans TBC169 group showed marked improvements of growth performance, nutrient digestibility and intestinal morphology compared with the other B. subtilis treatments. B. coagulans TBC169 supplementation improved the average body weight (BW), average daily weight gain (ADG), total tract apparent digestibility of crude protein and gross energy (GE), and reduced feed conversion rate (FCR) compared with the control group (P < 0.05). The villus height to crypt depth ratio (VH/CD) of jejunum and duodenum was increased in the birds fed with B. coagulans TBC169 compared with the control group (P < 0.05). However, two B. subtilis treatments presented more positive variation of the jejunum microflora of chickens than that in the B. coagulans TBC169 group. B. subtilis PB6 and B. subtilis DSM32315 treatments improved the diversity of jejunal microbiota on day 21 compared with the control (P < 0.05), while which were decreased on day 42 (P < 0.05). The supplementation with B. coagulans TBC169 significantly improved the proportion of Firmicutes, otherwise two B. subtilis significantly improved the proportion of Proteobacteria, Bacteroidetes, Actinobacteria, and Acidobacteria at the phylum level during starter phase and decreased the proportion of Bacteroidetes during growing phase compared with the control. The supplementation with B.subtilis DSM32315 significantly improved the proportion of Clostridiales during starter phase, whereas two B. subtilis significantly improved the proportion of Pseudomonas, Burkholderia, Prevotella, DA101 during growing phase at the genus level compared with the control. In conclusion, the dietary supplementation with probiotic Bacillus spp. strains improved body weight and intestinal morphology in broiler chickens, which might be associated with the gut microbiota.

Background β-Hydroxy-β-methylbutyrate (HMB) is the metabolite of leucine that plays an important role in muscle protein metabolism. The objective of the present study was to determine the effects of in ovo feeding (IOF) of HMB at 7 days of incubation (DOI) via air cell or 18 DOI via amnion on hatchability, muscle growth and performance in prenatal and posthatch broilers. Results IOF of HMB via air cell at 7 DOI increased hatchability by 4.34% compared with the control (89.67% versus 85.33%). Birds in IOF groups exhibited higher body weight, average daily body weight gain and pectoral muscle percentage. Furthermore, IOF of HMB significantly increased the level of plasma growth hormone, insulin and insulin-like growth factor-1. Chicks hatched from IOF treatment had larger diameters of muscle fiber and higher mitotic activity of satellite cells at early posthatch age. IOF of HMB activated satellite cells by upregulation of mRNA expression of myogenic transcription factors, myogenic differentiation one (MyoD) and myogenin. Chicks hatched from air cell injection group had higher pectoral muscle percentage at 5 d posthatch and greater satellite cell mitotic activity at 7 d posthatch than counterparts from amnion injection group. Conclusions IOF of HMB via amnion at 18 DOI or especially via air cell at 7 DOI could be used as an effective approach to enhance hatchability, productive performance and breast muscle yield in broilers. © 2019 Society of Chemical Industry.

Knowledge about the modulation of gut microbiota improves our understanding of the underlying mechanism by which probiotic treatment benefits the chickens. This study examined the effects of Bacillus subtilis DSM 32315 on intestinal structure and microbial composition in broilers. Broiler chicks were fed basal diets without or with B. subtilis supplementation (1.0 × 109 spores/kg of diet). Supplemental B. subtilis increased average body weight and average daily gain, as well as elevated villus height and villus height to crypt depth ratio of ileum in broilers. Multi-dimension analysis showed a certain degree of separation between the cecal microbiota from treatment and control groups. Increased Firmicutes abundance and reduced Bacteroidetes abundance in cecum were observed responded to B. subtilis addition, which also increased the abundances of Christensenellaceae and Caulobacteraceae, and simultaneously decreased the abundances of potentially harmful bacteria such as Vampirovibrio, Escherichia/Shigella and Parabacteroides. Network analysis signified that B. subtilis addition improved the interaction pattern within cecal microbiota of broilers, however, it exerted little influence on the metabolic pathways of cecal microbiota by comparison of the functional prediction of metagenomes. In conclusion, supplemental B. subtilis DSM 32315 improved growth performance and intestinal structure of broilers, which could be at least partially responsible by the manipulation of cecal microbial composition.

The responses of broiler chickens to dietary protein reduction were investigated in the presence of glycine and cysteine inclusion at the marginal deficiency of sulfur-containing amino acids. A total of 432 broiler chickens were allotted to six dietary treatments, SP1 is standard protein diet with 100% total sulfur amino acids (TSAA), SP2 is standard protein diet with 85% TSAA, RP is reduced protein diet without glycine and cysteine supplementation, RPC is reduced protein diet with cysteine supplementation at 0.1%, and RPG is reduced protein diet with 1% glycine supplementation, while RPGC is reduced protein diet with 0.1% cysteine and 1% glycine supplementation. In this study, 4.5% protein is reduced in diets&mdash, thus, 17.5% CP (crude protein) for starter phase and 15.5% CP for the grower phase. Reduced protein diets contained 85% TSAA. Broiler chickens fed standard protein diet SP2 had superior bodyweight (BW) (p &le, 0.05) in the starter and grower phase, average daily gain (ADG) (p &le, 0.05) in the starter and entire feeding period, average daily feed intake (ADFI) (p &le, 0.05) in the starter phase, and better feed conversion ratio (FCR) (p &le, 0.05) in the starter, grower and entire feeding period, however, RPGC showed higher ADG (p &le, 0.05) in the grower phase, and ADFI (p &le, 0.05) in the grower and entire feeding period. RPC and RPG diet improved BW (p &le, 0.05), ADG (p &le, 0.05), ADFI (p &le, 0.05), and better FCR (p &le, 0.05) in starter, grower, entire feeding period compared to RP. The RPGC group had higher BW (p &le, 0.05) and better FCR (p &le, 0.05) compared to the RPC group. Blood biochemical parameters showed that Broiler chickens fed on the SP2 diet had higher levels of total protein (TP) (p &le, 0.05), albumin (ALB) (p &le, 0.05), creatinine (CRE) (p &le, 0.05), and aspartate aminotransferase (AST) (p &le, 0.05) and, lower level of uric acid (UA) (p &le, 0.05), blood urea nitrogen (BUN) (p &le, 0.05), glucose (GLU) (p &le, 0.05), and alanine aminotransferase (ALT) (p &le, 0.05) in the starter phase, however, higher level of TP (p &le, 0.05), GLU (p &le, 0.05), CRE (p &le, 0.05), and AST (p &le, 0.05), and lower level of ALB (p &le, 0.05), UA (p &le, 0.05), and ALT (p &le, 0.05) in the grower phase, RPGC had higher level of TP (p &le, 0.05), ALT (p &le, 0.05) and AST (p &le, 0.05), BUN (p &le, 0.05), and CRE (p &le, however, in grower phase, RPGC had higher level of TP (p &le, 0.05), and ALB (p &le, 0.05), and lower level of UA (p &le, 0.05). Free amino acids profile showed that broiler fed on standard protein diet SP2 had reduced the methionine (p &le, 0.05) concentration, RPC increased the concentrations of taurine (p &le, 0.05), phosphoethanolamine (p &le, 0.05), threonine (p &le, 0.05), valine (p &le, 0.05), isoleucine (p &le, 0.05), phenylalanine (p &le, 0.05), ornithine (p &le, 0.05), and lysine (p &le, 0.05) and reduced the citrulline (p &le, RPG increased the concentration of glutamate (p &le, 0.05), glycine (p &le, 0.05), cysteine (p &le, 0.05), and arginine (p &le, 0.05), and decreased the concentration of tyrosine (p &le, 0.05), and RPGC increased the concentration of serine (p &le, 0.05) and reduced the concentration of hydroxyproline (p &le, 0.05). Serum metabolites analysis showed that reduced protein downregulated the 54 metabolites, however, glycine fortification up-regulated the Benzamide, Pro-Ser, N-Carbamylglutamate, D-gluconate, and Gamma-Glutamylcysteine. Carcass quality showed that SP2 decreased the abdominal fat percentage (p &le, 0.05). Nitrogen digestibility was higher by the diet RP (p &le, 0.05). This study demonstrated that protein content could be reduced up to 4.5% with 1% glycine and 0.1% cysteine fortification in diet, which has the potential to inhibit the adverse effect of reduced protein and attain the standard growth performance.

Octacosanol, which has prominent physiological activities and functions, has been recognized as a potential growth promoter in animals. A total of 392 1-d-old male Arbor Acres broiler chicks with similar body weight were randomly distributed into four dietary groups of seven replicates with 14 birds each supplemented with 0, 12, 24, or 36 mg octacosanol (extracted from rice bran, purity >92%)/kg feed. The feeding trial lasted for six weeks and was divided into the starter (day 1 to 21) and the grower (day 22 to 42) phases. The results showed that the feed conversion ratio (FCR) was significantly improved in broilers fed a diet containing 24 mg/kg octacosanol compared with those fed the control diet in the overall phase (day 1 to 42, p = 0.042). The average daily gain and FCR both showed linear effects in response to dietary supplementation of octacosanol during the overall phase (p = 0.031 and 0.018, respectively). Broilers fed with 24 or 36 mg/kg octacosanol diet showed a higher eviscerated yield, which increased by 5.88% and 4.26% respectively, than those fed the control diet (p = 0.030). The breast muscle yield of broilers fed with 24 mg/kg octacosanol diet increased significantly by 12.15% compared with those fed the control diet (p = 0.047). Eviscerated and breast muscle yield increased linearly with the increase in dietary octacosanol supplementation (p = 0.013 and 0.021, respectively). Broilers fed with 24 or 36 mg/kg octacosanol diet had a greater (p = 0.021) pH45min value in the breast muscle, which was maintained linearly in response to dietary octacosanol supplementation (p = 0.003). There was a significant decrease (p = 0.007) in drip loss value between the octacosanol-added and the control groups. The drip loss showed linear (p = 0.004) and quadratic (p = 0.041) responses with dietary supplementation of octacosanol. These studies indicate that octacosanol is a potentially effective and safe feed additive which may improve feed efficiency and meat quality, and increase eviscerated and breast muscle yield, in broiler chicks. Dietary supplementation of octacosanol at 24 mg/kg diet is regarded as the recommended dosage in the broilers' diet.

Previous studies showed that monochromatic green light stimuli during embryogenesis accelerated posthatch body weight (BW) and pectoral muscle growth of broilers. In this experiment, we further investigated the morphological and molecular basis of this phenomenon. Fertile broiler eggs (Arbor Acres, n=880) were pre-weighed and randomly assigned to 1 of the 2 incubation treatment groups: (1) dark condition (control group), and (2) monochromatic green light group (560 nm). The monochromatic lighting systems sourced from light-emitting diode lamps and were equalized at the intensity of 15 lx at eggshell level. The dark condition was set as a commercial control from day 1 until hatching. After hatch, 120 male 1-day-old chicks from each group were housed under incandescent white light with an intensity of 30 lx at bird-head level. No effects of light stimuli during embryogenesis on hatching time, hatchability, hatching weight and bird mortality during the feeding trial period were observed in the present study. Compared with the dark condition, the BW, pectoral muscle weight and myofiber cross-sectional areas were significantly greater on 7-day-old chicks incubated under green light. Green light also increased the satellite cell mitotic activity of pectoral muscle on 1- and 3-day-old birds. In addition, green light upregulated MyoD, myogenin and myostatin mRNA expression in late embryos and/ or newly hatched chicks. These data suggest that stimulation with monochromatic green light during incubation promote muscle growth by enhancing proliferation and differentiation of satellite cells in late embryonic and newly hatched stages. Higher expression of myostatin may ultimately help prevent excessive proliferation and differentiation of satellite cells in birds incubated under green light.

Beta-hydroxy-β-methylbutyrate (HMB), the metabolite of leucine, plays an important role in muscle protein metabolism. To investigate the effect of dietary HMB calcium (HMB-Ca) on growth performance, breast muscle development, and serum parameters in broiler chickens, a total of two hundred seventy 1-d-old Arbor Acres male broiler chicks were randomly allotted into 3 dietary treatments supplemented with 0, 0.05%, or 0.1% HMB-Ca during the starter (1 to 21 d) and grower (22 to 42 d) period. The results showed that broilers fed 0.1% HMB-Ca diet had higher ADG during the starter or the whole period, and gain 148 g more BW than the chicks fed the control diet at 42 d of age (P < 0.05). At 21 d of age, birds receiving 0.1% HMB-Ca had more breast muscle yield, less abdominal fat than the control, and more dressing percentage than birds fed the control or 0.05% HMB-Ca diet (P < 0.05). At 42 d of age, 0.1% HMB-Ca increased breast muscle yield than the control and decreased abdominal fat compared with the control or 0.05% HMB-Ca group (P < 0.05). In comparison with the control, feeding 0.1% HMB-Ca increased the triiodothyronine, thyroxine, triiodothyronine/thyroxine ratio and decreased the serum uric acid level at d 21 (P < 0.05). At 42 d of age, serum thyroxine level was elevated in the 0.05% HMB-Ca treatment, and the uric acid concentration was significantly decreased by the 0.1% HMB-Ca-supplemented diet (P < 0.05). Dietary HMB-Ca did not affect the growth hormone or insulin content. This study suggested that dietary supplementation of HMB-Ca improved growth performance, stimulated the breast muscle development, and decreased the abdominal fat deposition in broiler chickens, and the favorable effects were more pronounced in the starter phase. The growth promotion effect of HMB-Ca may be partly related to the increased serum thyroid hormones in broiler chickens.

The effect of transport stress on blood metabolism, glycolytic potential, and meat quality in broilers was investigated. Arbor Acres chicks (n = 360, 1 d old, males) were randomly allotted to 1 of 5 treatments: unstressed control, 45-min (short-term) transport with 45-min (short-term) recovery, 45-min transport with 3-h (long-term) recovery; 3 h (long-term) transport with 45-min recovery, and 3-h transport with 3-h recovery. Each treatment consisted of 6 replicates with 12 birds each. On d 46, all birds (except the control group) were transported according to a designed protocol. Transport time affected plasma glucose level (P

Previous studies showed that monochromatic green light stimuli during embryogenesis accelerated posthatch body weight and pectoral muscle growth of broilers. In this experiment, we further investigated whether the regulation of broiler embryonic or posthatch growth by green light stimulus during incubation is associated with the changes of some important hormones at different ages of embryos and broiler chickens. Fertile broiler eggs (Arbor Acres, n=880) were pre-weighed and randomly assigned 1 of 2 incubation treatment groups: i) dark condition (control group), and ii) monochromatic green light group (560 nm). The monochromatic lighting systems sourced from light-emitting diode lamps were equalised at the intensity of 15 lux (lx) at eggshell level. The dark condition was set as a commercial control from day one until hatching. After hatch, 120 day-old male chicks from each group were housed under white light with an intensity of 30 lx at bird-head level. Compared with the dark condition, chicks incubated under the green light showed significantly higher growth hormone (GH) levels from 19 d of embryogenesis (E19) to 5 d of posthatch (H5), and higher plasma insulinlike growth factor (IGF-I) levels from both E17 to E19 and H3 to H35. No significant differences were found in plasma thyroxine, triiodothyronine, and testosterone in embryos or hatched birds between the 2 groups. These results indicate that somatotropic axis hormones (GH and IGF-I) may be the most important contributor to chicken growth promoted by green light stimuli during embryogenesis.