N-Carbamylglutamate in ovo feeding improves carcass yield, muscle fiber development, and meat quality in broiler chickens.

BACKGROUND: Insufficient endogenous nutrients in the broiler embryo can lead to muscle gluconeogenesis, which ultimately affects the post-hatching performance of chicks. This study investigated the effects of in ovo feeding (IOF) of N-carbamylglutamate (NCG) on the growth hormones, carcass yield, and meat quality in broilers. Fertile eggs from a 30-week-old Ross 308 breeder flock were divided into three treatment groups: NC (non-injection), SC (100 µL saline-injection), and NCG (2 mg NCG injection). Each group had six replicates, with 70 eggs per replicate during incubation. Injections were administered on the 17.5th day of embryonic development. After hatching, 270 chicks were selected for 42-day rearing for further sampling. RESULTS: Chicks in the NCG group had significantly higher body weight (BW) and average daily gain (ADG) at the growing phase, increased growth and testosterone hormone in both feeding phases (21 and 42 days), and improved average daily gain (ADG) and food conversion ratio (FCR) in both grower and entire feeding phases (P < 0.05). Triiodothyronine (T3) and tetraiodothyronine (T4) levels, carcass yield, dressing, drum weight, breast muscle weight, drumstick weights, thighs, pectoralis major, and their part percentage of carcass were improved in the NCG group (P < 0.05), these effects were varied along feeding phases. Moreover, IOF of the NCG also improved pectoralis breast muscle color values at 24 h post mortem (P < 0.05). CONCLUSION: These results suggest that NCG injection at the late embryonic age of broiler enhances growth performance and meat quality throughout the lifespan and this can probably be attributed to an increase in thyroid and testosterone hormones, indicating potential involvement in metabolic and nutrient partitioning pathway regulation. © 2024 Society of Chemical Industry.

Decreased eggshell strength caused by impairment of uterine calcium transport coincide with higher bone minerals and quality in aged laying hens.

BACKGROUND: Deteriorations in eggshell and bone quality are major challenges in aged laying hens. This study compared the differences of eggshell quality, bone parameters and their correlations as well as uterine physiological characteristics and the bone remodeling processes of hens laying eggs of different eggshell breaking strength to explore the mechanism of eggshell and bone quality reduction and their interaction. A total of 240 74-week-old Hy-line Brown laying hens were selected and allocated to a high (HBS, 44.83 ± 1.31 N) or low (LBS, 24.43 ± 0.57 N) eggshell breaking strength group. RESULTS: A decreased thickness, weight and weight ratio of eggshells were observed in the LBS, accompanied with ultrastructural deterioration and total Ca reduction. Bone quality was negatively correlated with eggshell quality, marked with enhanced structures and increased components in the LBS. In the LBS, the mammillary knobs and effective layer grew slowly. At the initiation stage of eggshell calcification, a total of 130 differentially expressed genes (DEGs, 122 upregulated and 8 downregulated) were identified in the uterus of hens in the LBS relative to those in the HBS. These DEGs were relevant to apoptosis due to the cellular Ca overload. Higher values of p62 protein level, caspase-8 activity, Bax protein expression and lower values of Bcl protein expression and Bcl/Bax ratio were seen in the LBS. TUNEL assay and hematoxylin-eosin staining showed a significant increase in TUNEL-positive cells and tissue damages in the uterus of the LBS. Although few DEGs were identified at the growth stage, similar uterine tissue damages were also observed in the LBS. The expressions of runt-related transcription factor 2 and osteocalcin were upregulated in humeri of the LBS. Enlarged diameter and more structural damages of endocortical bones and decreased ash were observed in femurs of the HBS. CONCLUSION: The lower eggshell breaking strength may be attributed to a declined Ca transport due to uterine tissue damages, which could affect eggshell calcification and lead to a weak ultrastructure. Impaired uterine Ca transport may result in reduced femoral bone resorption and increased humeral bone formation to maintain a higher mineral and bone quality in the LBS.

Inclusion of guanidinoacetic acid in a low metabolizable energy diet improves broilers growth performance by elevating energy utilization efficiency through modulation serum metabolite profile.

This study was aimed to explore the elevating energy utilization efficiency mechanism for the potentially ameliorative effect of guanidinoacetic acid (GAA) addition on growth performance of broilers fed a low metabolizable energy (LME) diet. A total of 576 d old broilers were randomly allocated to one of the six treatments: a basal diet (normal ME, positive control, PC), or an LME diet (50 kcal/kg reduction in ME, negative control, NC) supplemented with 0.02%, 0.04%, 0.06%, and 0.08% GAA from 1 to 42 d of age, respectively. The GAA fortification in LME diet linearly or quadratically dropped (P < 0.05) the feed conversion ratio (FCR) from 22 to 42 and 1 to 42 d of age, abdominal fat rate on day 42, serum alanine aminotransferase (ALT) on day 21, and serum creatinine (CREAN) on days 21 and 42, elevated (P < 0.05) breast muscle rate and leg muscle rate on day 42, serum creatine kinase (CK) on days 21 and 42, as well as alkaline phosphatase (ALP), and lactate dehydrogenase (LDH) on day 21. The dietary optimal GAA levels were 0.03%-0.08% based on the best-fitted quadratic models (P < 0.03) of the above parameters. Thus, the PC, LME, and 0.04% GAA-LME groups were selected for further analysis. Serum essential amino acids (EAA) tryptophan, histidine and arginine, non-essential amino acids (NEEA) serine, glutamine and aspartic acid were significantly decreased (P < 0.05), compared to PC diet by LME or 0.04% GAA-LME diet. 0.04% GAA-LME group reversed (P < 0.05) the reduction of arginine, 3-methyhistidine, and 1-methylhistidine by LME diet. Besides, six birds at 28 d of age from LME and 0.04% GAA-LME groups were selected for energy utilization observation in calorimetry chambers. The results demonstrated that 0.04% GAA-LME group significantly improved (P < 0.05) the ME intake (MEI) and net energy (NE) compared to the LME diet. Overall, these findings suggest that 0.04% GAA is the ideal dose of broilers fed the LME diet, which can significantly improve the growth performance and carcass characteristics by modulation of creatine metabolism through elevating serum CK activity and arginine concentration.

Guanidinoacetic acid (GAA) has been found to elevate energy utilization efficiency in broilers; however, the underlying mechanisms remain unclear. We investigated the effects of GAA addition in low metabolizable energy (LME) diet on growth performance, carcass characteristics and serum biochemical indices of broilers, and found that GAA addition linearly or quadratically dropped the feed conversion ratio from 22 to 42 and 1 to 42 d of age, abdominal fat rate on day 42, serum alanine aminotransferase on day 21, and serum creatinine on days 21 and 42, elevated breast muscle and leg muscle rate on day 42, serum creatine kinase, alkaline phosphatase, as well as lactate dehydrogenase on days 21 or 22. The dietary optimal GAA levels were 0.03%-0.08% based on the best-fitted quadratic models of the above parameters. Thus, further analysis was conducted and found that 0.04% GAA reversed the reduction of arginine, 3-methyhistidine, and 1-methylhistidine and improved the ME intake and net energy compared to the LME diet. These findings suggested that 0.04% GAA is the ideal dose for enhancing the energy utilization of broilers fed the LME diet, GAA addition can significantly improve the growth performance by elevating energy utilization efficiency through modulation serum metabolite profile.

Uterine microbial communities and their potential role in the regulation of epithelium cell cycle and apoptosis in aged hens.

BACKGROUND: Alterations of the uterine microbiome are closely associated with various intrauterine diseases and physiological conditions, which are well-established in mammals. However, as representative oviparous animals, the research on the uterine microbial ecosystem and its functions with physiological homeostasis is limited in chickens. Additionally, continuous egg-laying disrupts the oviducal immune defenses of aged hens, susceptible to pathogen invasion, causing poor egg quality and food-borne infections in humans. Here, we investigated aging-related changes in the oviduct microbial colonization and transmission from the gut to eggs and their roles in a hen model. RESULTS: The results of 16S rDNA sequencing showed significant differences in the oviduct microbial composition between young (38 weeks) and aged (77 weeks) laying hens. SourceTracker analysis further revealed differences in the effects of microbial transmission on the oviducal microbiota between young and aged hens. Enhanced barrier defense with cell apoptosis suppression and cell cycle arrest of the uterus were observed in aged hens reducing microbial transmission from the lower to upper reproductive tract. In addition, a total of 361 significantly differential metabolites were identified using metabolomics in the aged uterine microbiota, especially in products of amino acid metabolism and biosynthesis of various secondary metabolites, which might have essential effects on cell apoptosis by regulating immune responses and cell cycle. Notably, antibiotics disrupted uterine microbiota by dietary intervention and direct perfusion did not retard aging-related physiological changes but further aggravated aging processes by disrupting the cell cycle and apoptosis. CONCLUSIONS: The microbiota continuum along the reproductive tract in aged birds differs from that in young birds, especially with a significant shift in the uterus. The aged uterine microbiota probably contributes to the regulation of cell cycle and apoptosis by microbial metabolites primarily involved in amino acid metabolism and biosynthesis of various secondary metabolites. These findings provide new insights into the roles of the reproductive tract microbiota in regulating the cell programming of the aged host, contributing to the exploration of the microbiome as a target for diagnosing aging health status and therapy for gynecological diseases in women. Video Abstract.

Biophysiology of in ovo administered bioactive substances to improve gastrointestinal tract development, mucosal immunity, and microbiota in broiler chicks.

Early embryonic exogenous feeding of bioactive substances is a topic of interest in poultry production, potentially improving gastrointestinal tract (GIT) development, stimulating immunization, and maximizing the protection capability of newly hatched chicks. However, the biophysiological actions and effects of in ovo administered bioactive substances are inconsistent or not fully understood. Thus, this paper summarizes the functional effects of bioactive substances and their interaction merits to augment GIT development, the immune system, and microbial homeostasis in newly hatched chicks. Prebiotics, probiotics, and synbiotics are potential bioactive substances that have been administered in embryonic eggs. Their biological effects are enhanced by a variety of mechanisms, including the production of antimicrobial peptides and antibiotic responses, regulation of T lymphocyte numbers and immune-related genes in either up- or downregulation fashion, and enhancement of macrophage phagocytic capacity. These actions occur directly through the interaction with immune cell receptors, stimulation of endocytosis, and phagocytosis. The underlying mechanisms of bioactive substance activity are multifaceted, enhancing GIT development, and improving both the innate and adaptive immune systems. Thus summarizing these modes of action of prebiotics, probiotics and synbiotics can result in more informed decisions and also provides baseline for further research.

Uterine inflammation status modulates eggshell mineralization via calcium transport and matrix protein synthesis in laying hens.

This study explored the effects of uterine inflammation on eggshell mineralization, ultrastructure and mechanical properties in laying hens modified by a lipopolysaccharide (LPS) challenge or dietary essential oil (EO) addition. In trial 1, a total of 72 Hy-line Brown layers at 36 wk of age were randomly assigned to 3 treatment groups (n = 8), where they were intravenously injected with phosphate buffered saline, LPS at 1 mg/kg body weight, or LPS 3 times at 24-h intervals. In trial 2, a total of 288 Hy-line Brown layers at 60 wk of age were randomly divided into 4 groups (n = 8), where they were fed basal diets supplemented with EO at 0, 50, 100 and 200 mg/kg for 12 wk. A uterine inflammation model was constructed with LPS treatment, indicated by the elevated expression of IL-1ß and TNF-α (P < 0.05) and lymphocyte infiltration. Uterine inflammation caused remarkable decreases in eggshell thickness and mechanical properties with structure deteriorations (P < 0.05). Uterine inflammation stimulated the expression of matrix proteins ovotransferrin (TF) and ovalbumin (OVAL), while depressing the mRNA levels of calbindin-1 (CALB1) and osteopontin in uterine mucosa (P < 0.05). In contrast, EO addition alleviated uterine inflammation, evidenced by depressed levels of IL-1ß and IL-6 (P < 0.05). There was a significant elevation in shell thickness and breaking strength following EO intervention (P < 0.05), and these effects were maximized at addition of 100 mg/kg. Further, EO improved shell ultrastructure including more early fusion, less type B mammillae, and increased effective thickness (P < 0.05). The alleviated inflammation decreased the expression of OVAL and TF, whereas ion transport genes like CALB1 and solute carrier family 26 member 9 were upregulated (P < 0.05). Our findings suggest that inflammatory status can impact uterine functions in calcium transport and the synthesis of matrix proteins especially such as OVAL and TF, which in turn modulates calcium precipitation and ultrastructure formation, thereby determining eggshell mechanical properties. These findings provide a novel insight into the uterine inflammation-mediated modifications of eggshell quality.

Improvement in growth performance and digestive function from amniotic injections of N-acetylglutamate in broiler chickens.

BACKGROUND: N-acetylglutamate (NAG) is the initial and essectial substrate in the process of de novo arginine synthesis, plays an important role in intestinal development. The aim of this study was to determine the effects of in ovo feeding of NAG, 1.5 mg/egg at 17.5 days of incubation (DOI) via amnion, on hatching performance, early intestinal histomorphometry, jejunal barrier, digestive function, and growth performance of broiler chickens between 1 and 14 days of age. RESULTS: Amniotic injection of NAG had no significant effect on hatching characteristics compared with the non-injected control group (NC group). Birds in the NAG solution-injected group (NAG group) exhibited lower average daily feed intake and better feed efficiency during a period of 1-14 days. In comparison with the NC group, the NAG group had decreased crypt depth (CD) in the ileum and increased villus height (VH) / CD in the jejunum at 7 days, and decreased CD in duodenum and significantly increased VH in the jejunum at 14 days. However, the effects of in ovo supplementation with NAG on the density of goblet cells, and gene expression of mucin 2 and alkaline phosphatase were not significant. Chicks in the NAG group had a significantly higher mRNA expression level of trypsin and maltase in jejunum at 7 days than the NC group but not at 14 days. CONCLUSION: Amniotic injections of NAG (1.5 mg/egg) at 17.5 DOI could improve early growth performance of broilers during 1-14 days after hatching by accelerating the development of the intestine and enhancing jejunal digestive function. © 2023 Society of Chemical Industry.

Recent Trends on Mitigative Effect of Probiotics on Oxidative-Stress-Induced Gut Dysfunction in Broilers under Necrotic Enteritis Challenge: A Review.

Gut health includes normal intestinal physiology, complete intestinal epithelial barrier, efficient immune response, sustained inflammatory balance, healthy microbiota, high nutrient absorption efficiency, nutrient metabolism, and energy balance. One of the diseases that causes severe economic losses to farmers is necrotic enteritis, which occurs primarily in the gut and is associated with high mortality rate. Necrotic enteritis (NE) primarily damages the intestinal mucosa, thereby inducing intestinal inflammation and high immune response which diverts nutrients and energy needed for growth to response mediated effects. In the era of antibiotic ban, dietary interventions like microbial therapy (probiotics) to reduce inflammation, paracellular permeability, and promote gut homeostasis may be the best way to reduce broiler production losses. The current review highlights the severity effects of NE; intestinal inflammation, gut lesions, alteration of gut microbiota balance, cell apoptosis, reduced growth performance, and death. These negative effects are consequences of; disrupted intestinal barrier function and villi development, altered expression of tight junction proteins and protein structure, increased translocation of endotoxins and excessive stimulation of proinflammatory cytokines. We further explored the mechanisms by which probiotics mitigate NE challenge and restore the gut integrity of birds under disease stress; synthesis of metabolites and bacteriocins, competitive exclusion of pathogens, upregulation of tight junction proteins and adhesion molecules, increased secretion of intestinal secretory immunoglobulins and enzymes, reduction in pro-inflammatory cytokines and immune response and the increased production of anti-inflammatory cytokines and immune boost via the modulation of the TLR/NF-ĸ pathway. Furthermore, increased beneficial microbes in the gut microbiome improve nutrient utilization, host immunity, and energy metabolism. Probiotics along with biosecurity measures could mitigate the adverse effects of NE in broiler production.

Glycosylated proteins with abnormal glycosylation changes are potential biomarkers for early diagnosis of breast cancer.

Conventional cancer management relies on tumor type and stage for diagnosis and treatment, which leads to recurrence and metastasis and death in young women. Early detection of proteins in the serum aids diagnosis, progression, and clinical outcomes, possibly improving survival rate of breast cancer patients. In this review, we provided an insight into the influence of aberrant glycosylation on breast cancer development and progression. Examined literatures revealed that mechanisms underlying glycosylation moieties alteration could enhance early detection, monitoring, and therapeutic efficacy in breast cancer patients. This would serve as a guide for the development of new serum biomarkers with higher sensitivity and specificity, providing possible serological biomarkers for breast cancer diagnosis, progression, and treatment.

Effects of dietary Clostridium butyricum and fructooligosaccharides, alone or in combination, on performance, egg quality, amino acid digestibility, jejunal morphology, immune function, and antioxidant capacity of laying hens.

The present study was conducted to evaluate the effects of Clostridium butyricum (CB) and fructooligosaccharide (FOS) singly or combined, on performance, egg quality, amino acid digestibility, jejunal morphology, immune function and antioxidant capacity in peak-phase laying hens. A total of 288 Hy-Line Brown laying hens (30 weeks of age) were randomly assigned to 4 dietary groups that included basal diet, basal diet +0.02% of CB (zlc-17: 1 × 109 CFU/g) (PRO), basal diet +0.6% FOS (PRE), and basal diet +0.02% CB + 0.6% FOS (SYN) for 12 weeks. Each treatment had 6 replicates with 12 birds each. The results demonstrated that probiotics (PRO), prebiotics (PRE) and synbiotics (SYN) (p ≤ 0.05), respectively, exerted a positive effect on the performance and physiological response of the birds. There were significant increases in egg production rate, egg weight, egg mass, daily feed intake and reduced number of damaged eggs. and zero mortality rate due to dietary PRO, PRE and SYN (p ≤ 0.05) respectively. Also, feed conversion was improved by PRO (p ≤ 0.05). In addition, egg quality assessment showed that; eggshell quality was increased by PRO (p ≤ 0.05) and albumen indices (Haugh unit, thick albumen content, and albumen height) were enhanced by PRO, PRE and SYN (p ≤ 0.05). Further analysis showed that PRO, PRE and SYN (p ≤ 0.05), reduced heterophil to lymphocyte ratio, increased antioxidant enzymes and immunoglobulin concentration. Although spleen index was higher for PRO (p ≤ 0.05) group. The significant increase in villi height, villi width, villi height to crypt depth ratio and reduced crypt depth were obvious for PRO, PRE, and SYN (p ≤ 0.05). Furthermore, improved nutrient absorption and retention evidenced by increased digestibility of crude protein and amino acids, were notable for PRO, PRE, and SYN (p ≤ 0.05) group. Collectively, our findings revealed that dietary CB and FOS alone, or combined, enhanced productive performance, egg quality, amino acid digestibility, jejunal morphology, and physiological response in peak-phase laying hens. Our results would provide direction on nutritional strategies for gut enhancers and better physiological response of peak laying hens.

Yeast cell-wall polysaccharides improve immunity and attenuate inflammatory response via modulating gut microbiota in LPS-challenged laying hens.

Effects of dietary supplementation of yeast cell-wall polysaccharides (YCWP) on production performance, ileal microbial composition, immunomodulatory and anti-inflammatory effects in LPS-challenged laying hens, were evaluated. A total of 288 35-week-old Hy-Line Brown layers were randomly assigned into 4 dietary treatments: 0, 250, 500 and 1000 mg/kg YCWP, respectively. After a 12-week feeding period, a total of 32 birds were selected from the control (n = 16) and 1000 mg/kg YCWP group (n = 16). For each group, half (n = 8) received Escherichia coli LPS and half (n = 8) received PBS at 1 mg/kg body weight, intravenously. Results showed that YCWP enhanced feed efficiency and egg production linearly, with optimal laying performance notable in the 1000 mg/kg YCWP group. Dietary YCWP enhanced serum IgM and expression of ileal avian ß-defensin, alleviated the LPS-induced elevated levels of serum IL-6 and IL-1ß and the up-regulated expression of IL-1ß, TNF-α, IFN-γ, and IL-6 in spleen and/or ileal mucosa. Furthermore, anti-inflammatory and immunomodulatory effects of YCWP were linked with its enhancement effect on microbial diversity, proliferation of Bifidobacteriaceae, Lactocillus, Candidatus_Arthromitus, Streptomyces, Bacillaceae, and Desulfovibrio, and reduced abundance of Shigella. Therefore, YCWP has the potentials to be utilized as safe prebiotics and gut enhancer in laying hens.

Comparison of amino acid digestibility of soybean meal, cottonseed meal, and low-gossypol cottonseed meal between broilers and laying hens.

OBJECTIVE: This study aimed to determine and compare the apparent ileal digestibility (AID) and the standardized ileal digestibility (SID) of amino acids (AA) in soybean meal (SBM), cottonseed meal (CSM), and low-gossypol cottonseed meal (LCSM) fed to broiler chickens and laying hens. METHODS: Three semi-purified diets containing the identical crude protein concentration at 20% were formulated to contain SBM, CSM, or LCSM as the sole source of N. A N-free diet was also formulated to estimate the basal ileal endogenous losses of AA for broilers and hens. A total of 300 male Ross 308 chicks at one-day-old and 144 Hy-Line Brown laying hens at 30-week-old with initial egg production rate of 88.3%±1.0% were randomly allocated into 1 of 4 dietary treatments, respectively. RESULTS: CSM and LCSM showed more Arg and Cys+Met while less Lys, Ile, Leu, and Thr relative to SBM. Significant interactions existed between species and experimental diets for AID (except for Arg, Asp, Glu, Gly, and Pro) and SID (except for Arg, His, and Phe) of most AA. Most AA in diets showed higher AID (except for Lys) and SID (except for Lys, Met, and Ser) in broilers relative to laying hens. The AID and SID of all AA were significantly different between the three diets. In broilers, the AID and SID of most indispensable AA except for Arg in SBM and LCSM was higher than CSM. In laying hens, the AID and SID of most indispensable AA except for Arg, Met+Cys, and Phe in SBM was higher than CSM and LCSM. CONCLUSION: The accurate determination of AID and SID of AA in CSM and LCSM for broilers and layers benefits the application of CSM and LCSM in chicken diets. The cottonseed by-products CSM or LCSM showed the species-specific AA digestibility values for broilers and layers.

Effects of Saccharomyces cerevisiae hydrolysate on growth performance, immunity function, and intestinal health in broilers.

The current study was performed to explore the effects of dietary supplementation of Saccharomyces cerevisiae hydrolysate (SCH) on growth performance, immune function, and intestinal health in broiler chicken. A total of 300 Ross 308 male broilers (1-day-old) were randomly assigned to 2 dietary treatments including a basal diet (control group), and a basal diet supplemented with SCH feed additive (500 mg/kg in starter and grower phase, and 250 mg/kg in finisher phase). Each treatment had 6 replicates with 25 birds each. The results showed that the addition of SCH promoted growth during d 15 to 28 (P < 0.05). Although the addition of SCH had no significant effect on the intestinal relative indexes, it significantly increased the jejunum villus height (VH) and the ratio of villus height to crypt depth (VCR) of jejunum, and decreased the crypt depth (CD) of ileum (P < 0.05). Furthermore, SCH addition significantly downregulated the mRNA expression of immunomodulatory genes (TNF-α, IL-1ß, and IL-6), and upregulated the tight junction genes (ZO-1 and Claudin-1) (P < 0.05). High throughput sequencing analysis of bacterial 16S rRNA revealed that dietary SCH supplementation altered cecum microbiota. Alpha diversity analysis showed that a higher bacterial richness in cecum of broilers fed with SCH. The composition of cecum microbiota regulated by SCH addition was characterized by an increased abundance of Firmicutes and a reduced abundance of Bacteroidetes. At the genus level, dietary SCH resulted in a decrease of Bacteroides and an increase of short-chain fatty acids (SCFA) -producing bacteria including Lactobacillus and Faecalibacterium. Taken together, dietary SCH supplementation can stimulate the growth of broilers by regulating the intestinal immunity and barrier function, and improving the intestinal morphology, which may be related to the enhancement of bacterial diversity and the changes of intestinal microbial composition.

Bio-Fermented Malic Acid Facilitates the Production of High-Quality Chicken via Enhancing Muscle Antioxidant Capacity of Broilers.

Malic acid, an intermediate of the tricarboxylic acid (TCA) cycle, is a promising acidifier with strong antioxidant capacity. This study aimed to evaluate the effects of bio-fermented malic acid (BFMA) on promoting the body health, performance and meat quality of broilers. A total of 288 one-day-old Arbor Acres male broiler chicks were randomly divided into four treatments with six replicates in each. Every replicate had 12 chicks. Four experimental diets contained 0, 4, 8, and 12 g/kg BFMA, respectively. During the 42-day trial, mortality was recorded daily, feed intake and body weight of each replicate being recorded every week. Blood samples were collected on days 21 and 42 for chemical analysis. After slaughter at the age of 42 days, the carcass traits and meat quality of the broilers were measured, breast muscle samples were collected for the determination of antioxidant capacity, and cecal digesta were pretreated for microbiota analysis. Dietary BFMA significantly increased feed intake and daily gain, and decreased feed conversion ratio and death and culling ratio of the broilers at the earlier stage. The water-holding capacity of breast muscle indicated by the indexes of dripping loss and cooking loss was significantly increased by BFMA, especially at the addition level of 8 g/kg. Dietary BFMA significantly decreased the activity of superoxide dismutase and contents of immunoglobulin A and glutathione, and increased contents of immunoglobulin G and M in serum of the broilers. The contents of glutathione, inosinic acid, and total antioxidant capacity and the activities of glutathione-Px and superoxide dismutase were significantly increased by dietary BFMA, with the level of 8 g/kg best. The diversity of cecal microbiota of broilers was obviously altered by BFMA. In conclusion, as one of several acidifiers, addition of BFMA in diets could improve the performance and body health of broilers, probably by reinforcing immunity and perfecting cecal microbiota structure. As one of the intermediates of the TCA cycle, BFMA increases the water-holding capacity of breast muscle of broilers, probably through reducing lactate accumulates and enhancing antioxidant capacity.

A Comparison between the Egg Yolk Flavor of Indigenous 2 Breeds and Commercial Laying Hens Based on Sensory Evaluation, Artificial Sensors, and GC-MS.

The focus of this study was to compare the yolk flavor of eggs from laying hens of Chinese indigenous and commercial, based on detection of volatile compounds, fatty acids, and texture characteristics determination, using sensory evaluation, artificial sensors (electronic nose (E-nose), electronic tongue (E-tongue)), and gas chromatography-mass spectrometry (GC-MS). A total of 405 laying hens (Hy-Line Brown (n = 135), Xueyu White (n = 135), and Xinyang Blue (n = 135)) were used for the study, and 540 eggs (180 per breed) were collected within 48 h of being laid and used for sensory evaluation and the instrument detection of yolk flavor. Our research findings demonstrated significant breed differences for sensory attributes of egg yolk, based on sensory evaluation and instrument detection. The milky flavor, moisture, and compactness scores (p < 0.05) of egg yolk from Xueyu White and Xinyang Blue were significantly higher than that of Hy-Line Brown. The aroma preference scores of Xinyang Blue (p < 0.05) were significantly higher, compared to Hy-Line Brown and Xueyu White. The sensor responses of WIW and W2W from E-nose and STS from E-tongue analysis were significantly higher foe egg yolks of Hy-Line Brown (p < 0.05), compared to that of Xueyu White and Xinyang Blue. Additionally, the sensor responses of umami from E-tongue analysis, was significantly higher for egg yolks of Xueyu White (p < 0.05), compared to that of Hy-Line Brown and Xinyang Blue. Besides, the contents of alcohol and fatty acids, such as palmitic acid, oleic acid, and arachidonic acid, in egg yolk were positively correlated with egg flavor. The texture analyzer showed that springiness, gumminess, and hardness of Hy-Line Brown and Xueyu White (p < 0.05) were significantly higher, compared to Xinyang Blue. The above findings demonstrate that the egg yolk from Chinese indigenous strain had better milky flavor, moisture, and compactness, as well as better texture. The egg yolk flavors were mainly due to presence of alcohol and fatty acids, such as palmitic acid, oleic acid, and arachidonic acid, which would provide research direction on improvement in egg yolk flavor by nutrition. The current findings validate the strong correlation between the results of egg yolk flavor and texture, based on sensory evaluation, artificial sensors, and GC-MS. All these indicators would be beneficial for increased preference for egg yolk flavor by consumers and utilization by food processing industry, as well as a basis for the discrimination of eggs from different breeds of laying hens.

Dietary organic acids ameliorate high stocking density stress-induced intestinal inflammation through the restoration of intestinal microbiota in broilers.

BACKGROUND: High stocking density (HSD) stress has detrimental effects on growth performance, intestinal barrier function, and intestinal microbiota in intensive animal production. Organic acids (OA) are widely used as feed additives for their ability to improve growth performance and intestinal health in poultry. However, whether dietary OA can ameliorate HSD stress-induced impaired intestinal barrier in broilers remains elusive. In this study, a total of 528 one-day-old male Arbor Acres broilers were randomly allocated into 3 treatments with 12 replicates per treatment including 10 birds for normal stocking density and 17 birds for HSD. The dietary treatments were as follows: 1) Normal stocking density + basal diet; 2) HSD + basal diets; 3) HSD + OA. RESULTS: HSD stress can induce increased levels of serum corticosterone, lipopolysaccharides, interleukin-1ß, tumor necrosis factor-α, and down-regulated mRNA expression of ZO-1, resulting in compromised growth performance of broilers (P < 0.05). Dietary OA could significantly reduce levels of serum corticosterone, lipopolysaccharides, interleukin-1ß, and tumor necrosis factor-α, which were accompanied by up-regulated interleukin-10, mRNA expression of ZO-1, and growth performance (P < 0.05). Moreover, OA could down-regulate the mRNA expression of TLR4 and MyD88 to inhibit the NF-κB signaling pathway (P < 0.05). Additionally, HSD stress significantly decreased the abundance of Bacteroidetes and disturbed the balance of microbial ecosystems, whereas OA significantly increased the abundance of Bacteroidetes and restored the disordered gut microbiota by reducing competitive and exploitative interactions in microbial communities (P < 0.05). Meanwhile, OA significantly increased the content of acetic and butyric acids, which showed significant correlations with intestinal inflammation indicators (P < 0.05). CONCLUSIONS: Dietary OA ameliorated intestinal inflammation and growth performance of broilers through restoring the disordered gut microbial compositions and interactions induced by HSD and elevating short-chain fatty acid production to inhibit the TLR4/NF-κB signaling pathway. These findings demonstrated the critical role of intestinal microbiota in mediating the HSD-induced inflammatory responses, contributing to exploring nutritional strategies to alleviate HSD-induced stress in animals.

Enhancing egg production and quality by the supplementation of probiotic strains (Clostridium and Brevibacillus) via improved amino acid digestibility, intestinal health, immune response, and antioxidant activity.

This study focused on evaluating the influence of Clostridium butyricum and Brevibacillus strains on egg production, egg quality, immune response and antioxidant function, apparent fecal amino acid digestibility, and jejunal morphology when supplemented as probiotics in the diets of laying hens in the peak phase. A total of 288 healthy 30-week-old Hy-Line Brown laying hens were arbitrarily assigned to four dietary groups, which included control diet and control diet supplemented with 0.02% C. butyricum zlc-17, C. butyricum lwc-13, or Brevibacillus zlb-z1, for 84 days. The results showed that dietary C. butyricum and Brevibacillus sp. exerted a positively significant influence (P ≤ 0.05) compared to the control group on the performance, egg quality, and physiological response of the birds. The diets could reduce mortality rate and enhance (P ≤ 0.05) egg weight and egg mass, egg production rate, and feed efficiency. Further analysis suggested that the probiotic strains can enhance (P ≤ 0.05) eggshell quality, Haugh unit, thick albumen content, and albumen height. Also, probiotics enhanced (P ≤ 0.05) the antioxidant status via increased antioxidant enzymes and jejunal morphology as evidenced by increased villi surface area (VSA), the ratio of villi height to crypt depth, villi width, and villi height, and a significant reduction in crypt depth. Besides, nutrient absorption and retention were enhanced, as apparent fecal amino acid digestibility of key essential amino acids was substantially improved in the diet-based group. The concentrations of immunoglobulin M and A (IgM and IgA) increased significantly (P ≤ 0.05) in the probiotics group and the same effect was notable for complement proteins (C3) and immune organ (Spleen). Conclusively, the supplementation of Clostridium butyricum zlc-17 in comparison to Clostridium butyricum lwc-13 and Brevibacillus zlb-z1 strains significantly (P ≤ 0.05) promoted the antioxidant status, modulated the intestinal structure, enhanced amino acid digestibility, and regulated the immunity index of the laying hens, which finally improves the laying performance and egg quality of the laying hens.

Effects of rearing systems on the eggshell quality, bone parameters and expression of genes related to bone remodeling in aged laying hens.

Public concerns regarding animal welfare are changing the selection of rearing systems in laying hens. This study investigated the effects of rearing systems on eggshell quality, bone parameters and relative expression levels of genes related to bone remodeling in aged laying hens. A total of 2,952 55-day-old Jing Tint Six pullets were randomly assigned to place in the conventional caging system (CCS) or aviary system (AVS) and kept until 95 weeks of age. The AVS group delayed the decrease of eggshell quality and alleviated the symptoms of osteoporosis in the humerus rather than in the femur. Eggshell breaking strength, thickness, weight, weight ratio, stiffness and fracture toughness were decreased linearly with age (from 55 to 95 weeks of age, p < 0.05). The AVS group had higher eggshell breaking strength, stiffness and fracture toughness than the CCS group (p < 0.05). Higher total calcium and phosphorus per egg were presented in the AVS group at 95 weeks of age (p < 0.05). At 95 weeks of age, the AVS group had a humerus with higher weight, volume, length, midpoint perimeter, cortical index, fat-free dry weight, ash content, total calcium per bone, total phosphorus per bone, average bone mineral density, strength, stiffness and work to fracture compared to the CCS group (p < 0.05). Such differences did not appear in the femur. The relative expression levels of alkaline phosphatase (ALP) and osteocalcin (OCN) genes in the femur and hormone receptors (vitamin D receptor (VDR), estrogen receptor alpha (ERα) and fibroblast growth factor 23 (FGF23)) genes in the humerus were significantly upregulated (p < 0.05) in the AVS group. The level of tartrate-resistant acid phosphatase (TRAP) transcripts was also increased (p < 0.05) in the femur of the AVS group. Overall, compared with the CCS, the AVS alleviated the deterioration of eggshell and bone qualities of aged laying hens, which may be related to the changes in the expression of genes associated with bone remodeling.

Potential Feed Additives as Antibiotic Alternatives in Broiler Production.

This article aimed to describe the current use scenario, alternative feed additives, modes of action and ameliorative effects in broiler production. Alternative feed additives have promising importance in broiler production due to the ban on the use of certain antibiotics. The most used antibiotic alternatives in broiler production are phytogenics, organic acids, prebiotics, probiotics, enzymes, and their derivatives. Antibiotic alternatives have been reported to increase feed intake, stimulate digestion, improve feed efficiency, increase growth performance, and reduce the incidence of diseases by modulating the intestinal microbiota and immune system, inhibiting pathogens, and improving intestinal integrity. Simply, the gut microbiota is the target to raise the health benefits and growth-promoting effects of feed additives on broilers. Therefore, naturally available feed additives are promising antibiotic alternatives for broilers. Then, summarizing the category, mode of action, and ameliorative effects of potential antibiotic alternatives on broiler production may provide more informed decisions for broiler nutritionists, researchers, feed manufacturers, and producers.

The Role of Incubation Conditions on the Regulation of Muscle Development and Meat Quality in Poultry.

Muscle is the most abundant edible tissue in table poultry, which serves as an important source of high protein for humans. Poultry myofiber originates in the early embryogenic stage, and the overall muscle fiber number is almost determined before hatching. Muscle development in the embryonic stage is critical to the posthatch muscle growth and final meat yield and quality. Incubation conditions including temperature, humidity, oxygen density, ventilation and lighting may substantially affect the number, shape and structure of the muscle fiber, which may produce long-lasting effect on the postnatal muscle growth and meat quality. Suboptimal incubation conditions can induce the onset of myopathies. Early exposure to suitable hatching conditions may modify the muscle histomorphology posthatch and the final muscle mass of the birds by regulating embryonic hormone levels and benefit the muscle cell activity. The elucidation of the muscle development at the embryonic stage would facilitate the modulation of poultry muscle quantity and meat quality. This review starts from the physical and biochemical characteristics of poultry myofiber formation, and brings together recent advances of incubation conditions on satellite cell migration, fiber development and transformation, and subsequent muscle myopathies and other meat quality defects. The underlying molecular and cellular mechanisms for the induced muscle growth and meat quality traits are also discussed. The future studies on the effects of external incubation conditions on the regulation of muscle cell proliferation and meat quality are suggested. This review may broaden our knowledge on the regulation of incubation conditions on poultry muscle development, and provide more informative decisions for hatchery in the selection of hatching parameter for pursuit of more large muscle size and superior meat quality.