Secondary Functions of Arginine and Sulfur Amino Acids in Poultry Health: Review

Tibial adaptations to dietary 25-hydroxyvitamin D3 supplementation under two distinct vitamin regimens in young ducks

Tibia disorders in modern ducks are frequently associated with rapid weight gain and compromised bone quality, which is defined as the structural and material properties of bone tissue that determines its strength and fracture resistance. These factors significantly increase the risk of fractures and chronic pain. Studies suggest that 25-hydroxycholecalciferol (25-OH-D3), a vitamin D3 metabolite, effectively addresses bone disorders, potentially depending on dietary vitamin regimens, which are determined by the amount and ratio of vitamins in the diet. This study used a 2 × 2 factorial design to evaluate the effects of two vitamin regimens (regular and high) with or without exogenous 25-OH-D3 (0.069 mg/kg) on leg health and tibia quality in meat ducks (1-14 d). The high-vitamin regimen contained greater amounts of all vitamins except biotin and significantly enhanced ash content, tibial microstructure, fracture load, and reduced tibial dyschondroplasia (TD) scores (P < 0.05) compared to the regular regimen, despite no impact on growth performance or tibia length, weight, and diameter (P > 0.05). Additionally, dietary 25-OH-D3 supplementation increased weight gain (P < 0.05), improved bone quality, and strengthened bone formation and resorption processes. Notably, under the regular vitamin regimen, 25-OH-D3 reduced TD scores and enhanced weight gain, tibia mechanical properties, and the serum content of procollagen type I N-terminal propeptide (PN1P) that a marker of bone formation (all P < 0.05). However, these effects were diminished in ducks fed the high-vitamin diet. There were some interactions that were noticed regarding serum 25-OH-D3 content, trabecular area, tibia fracture load, and PN1P levels in the present study (P < 0.05). In conclusion, the biochemical effects of 25-OH-D3 were influenced by the baseline levels of dietary vitamins, a high-vitamin diet or treatment with 25-OH-D3 in a regular vitamin diet improved bone quality and reduced tibial dyschondroplasia by enhancing bone formation.

Recent advances in protein and amino acid nutritional dynamics in relation to performance, health, welfare, and cost of production

Amino acids are the foundation of numerous metabolic and physiological pathways for skeletal muscle accretion, internal organ development, skeletal development, and immune function. One widely studied subject in monogastric nutrition is dietary crude protein. However, birds do not have a crude protein requirement but have a clear requirement for essential amino acids. As individual amino acid requirements of swine and poultry are investigated and modern feed formulation tools and feed-grade amino acids are available cost-effectively, the dynamics of how we look at crude protein in the feed have evolved. With the modern tools available, nutritionists are able to formulate the feed to meet the amino acids required for optimal performance of animals. This approach reduces the excess nitrogen in the feed, making the diets friendlier for the gut, reducing substrates for harmful proliferating bacteria, reducing nitrogen excretion in manure, and improving the ecology and sustainability. Apart from growth, amino acids have a functional role in the metabolic and physiological pathways. Amino acids like threonine and arginine have additional functional roles in intestinal turnover, immune function, wound healing, vasodilation and oxidative, and heat stress alleviation. Such specific amino acids can be increased in the diet to support the physiological needs during the growth of animals without increasing the unwanted dietary nitrogen content. As the industry moves toward reducing crude protein while meeting the essential amino acid needs, more research is needed to understand the requirement of specific lower limiting and non-limiting amino acids as well as the dynamics of those amino acids in health, welfare, cost of production and ecological impact in poultry and swine production.

Effect of Ideal Amino Acid Ratio of Arginine to Lysine on Intake, Nutrient Digestibility, Growth Performance, Antibody Titers of Newcastle Disease and Infectious Bronchitis Disease, and Carcass Characteristics of Broilers

This study aimed to assess the effects of different arginine (Arg) to lysine (Lys) ratios on feed intake, nutrient digestibility, growth performance, carcass characteristics, and antibody titers of Newcastle disease (ND) and infectious bronchitis (IB) disease in broilers during 35 days of trial. For this purpose, a total of 816 day-old broiler birds having an average weight of 38 ± 3 g were divided into six dietary treatments in such a way that each treatment had eight replicates and each replicate had 17 birds. The treatments were 0.95 (1.19/1.25, 1.12/1.18, and 1.05/1.1), 1 (1.25/1.25, 1.18/1.18, and 1.1/1.1), 1.05 (1.31/1.25, 1.24/1.18, and 1.17/1.1), 1.10 (1.38/1.25, 1.30/1.18, and 1.23/1.1), 1.15 (1.44/1.25, 1.36/1.18, and 1.28/1.1), and 1.20 (1.50/1.25, 1.42/1.18, and 1.34/1.1) Arg/Lys divided into different amounts according to the nutritional needs of starter, grower, and finisher diets, respectively. The results showed that in the finisher phase, the FI was influenced cubically, while in the overall period, a quadratic effect was observed for the FI (p < 0.05). The results of BWG showed that BWG was linearly increased in birds given different Arg/Lys in the grower, finisher, and overall period (p < 0.05). The results also showed that during the grower, finisher, and overall phases, the body weight gain (BWG) was better in birds fed with 1.05 and 1.10 Arg/Lys (p < 0.05). Furthermore, a better feed conversion ratio (FCR) was shown in the starter and grower phases at 1.10 and 1.15 Arg/Lys (p < 0.05). The results of nutrient digestibility explored showed that the experimental treatments had a better effect (p < 0.05) on dry matter and crude fat digestibility in birds fed with 1.19/1.25, 1.12/1.18, and 1.05/1.1 and 1.25/1.25, 1.18/1.18, and 1.1/1.1 Arg/Lys in their diets while the crude protein digestibility remained unaffected with different treatments (p > 0.05). The treatments had no effect (p > 0.05) on relative organ weights, immune organs, and carcass characteristics. However, higher titers of ND and IBD were observed in birds fed with Arg/Lys of 1.38/1.25, 1.30/1.18, and 1.23/1.1 and 1.50/1.25, 1.42/1.18, and 1.34/1.1 in their diets (p < 0.05). Based on the results of the current study, it is concluded that the inclusion levels of 1.38/1.25, 1.30/1.18, and 1.23/1.1, and 1.44/1.25, 1.36/1.18, and 1.28/1.1 Arg/Lys resulted in better growth performance and immune response in the broiler birds, respectively. Therefore, adjusting the levels of Arg/Lys in feed is recommended to enhance broilers' growth performance and immune response.

Gender-Specific effects of L-arginine supplementation on bone mineral density and trabecular bone volume in Sprague-Dawley rats; stereological study

BACKGROUND

L-arginine (Arg) is a semi-essential amino acid that can be used as a key mediator for the release of growth hormone (GH), insulin-like growth factor-1(IGF-1), and other growth factors. In this study, we comprehensively evaluated the effect of Arg intake on bone growth and associated markers.

METHODS

The study involved 24 Sprague-Dawley rats (12 males, 12 females) divided into two groups (Age = 24 days). One group received a standard diet, while the other was injected with 10 mg/kg of Arg daily for 90 days. Serum bone markers like calcium (Ca), phosphorous(P), and alkaline phosphatase (ALP) were analyzed via colorimetric assays. stereological study and bone mineral density (BMD) were conducted via dissector method and Hologic Dual-energy x-ray absorptiometry (DXA) system; respectively.

RESULTS

Biochemical assays showed no significant differences in Ca, P, and ALP levels between groups. Male rats in the case group exhibited lower testosterone levels (p.value = 0.009). Stereological and bone mineral density (BMD) analyses revealed contrasting gender-specific outcomes. Female rats in the case group had higher BMD (p.value = 0.001), while males had lower BMD compared to controls (p.value = 0.018). Arg consumption affects trabecula volume values differently in females compared to males (p.value = 0.022). Furthermore, the study observed decreased osteocytes and osteoblasts in male case rats. The gender-based differences in BMD were attributed to Arg's paradoxical impact on testosterone levels in males.

CONCLUSION

Overall, Arg supplementation was found to influence BMD and trabecular bone volume, with outcomes varying depending on gender. The study highlights the intricate interplay between Arg, sex hormones, and bone health, offering insights into these complex relationships.

SYNLAC prime probiotics enhances growth performance, and resistance of white shrimp, Penaeus vannamei to Enterocytozoon hepatopenaei and Vibrio alginollyticus: Insights into immune and metabolic pathway modulations

This study explores the impact of SYNLAC Prime probiotics on the growth performance, health status, and metabolic profile of white shrimp, Penaeus vannamei. Shrimp fed with the experimental diets, including the control diet without probiotic supplementation, and the diets supplemented with SYNLAC Prime probiotics at concentrations of 105 CFU (g diet)-1 (P5) and 106 CFU (g diet)-1 (P6) for 56 days. Results indicated a significant enhancement in growth performance in probiotic-treated shrimp relative to the control group, attributed to structural improvements in the digestive tract, particularly the increased abundances of B cells in the hepatopancreas. The administration of dietary probiotics markedly reduced the severity of Enterocytozoon hepatopenaei (EHP) infection and decreased cumulative mortalities following Vibrio alginolyticus challenge. Shrimp in the P6 group exhibited significant elevations in phenoloxidase activity, respiratory burst, lysozyme activity and phagocytic activity compared to control group. Furthermore, there was an upregulation of several immune-related genes in hepatopancreas, including serine protease (SP), prophenoloxidase (proPO) I, proPO II, and penaeidin 3a. Additionally, the expression of β-1, 3-glucan binding protein and SP mRNA was significantly increased in hemocytes. Untargeted metabolomics analysis using LC-MS/MS revealed significant changes in the hepatopancreas metabolic profile, highlighting alterations in energy metabolisms pathways, such as citrate cycle and nicotinate and nicotinamide metabolism, as well as amino acid metabolisms pathways including arginine and proline metabolism, taurine and hypotaurine metabolism, and histidine metabolism. These findings underscore the potential of SYNLAC Prime probiotics in enhancing shrimp growth, immune function, and metabolic pathways, offering valuable insights for advancing health management strategies in shrimp aquaculture.

Metabolomic analysis reveals altered amino acid metabolism and mechanisms underlying Eimeria infection in laying hens

Avian coccidiosis, caused by Eimeria spp, is a devastating disease in laying hens. Previous studies have suggested that amino acids may be involved in Eimeria infection of broiler chickens. However, their metabolic features in laying hens, as well as the effect of multiple Eimeria species challenges on poultry hosts have not been elucidated yet. Here, a targeted metabolomics approach was employed to identify altered amino acid metabolism and mechanisms in laying hens with multiple Eimeria species challenges. Laying hens, Hy-Line W-36 aged 25 wk, were randomly assigned to a control group and groups inoculated with varying levels of mixed Eimeria species (E. maxima, E. tenella, and E. acervulina). Serum samples from each group were collected at 6 d and 14 d of postinoculation (6 and 14 DPI) for metabolite profiling. Metabolomic analysis revealed notable metabolic variations between control and infected groups, especially at 6 DPI stage. Varying levels of Eimeria dosages did not show a significant metabolic difference, and metabolites were sensitive to low-level infection. With statistical analysis, differentially expressed compounds (3-methylhistidine, alanine, aspartate, lysine, asparagine, methionine, ornithine, and tryptophan) were selected, and their metabolic network was identified by pathway enrichment analysis. In the network, the lysine biosynthesis pathway was upregulated, while the arginine and proline metabolic pathway was downregulated under infection. Other pathways showed complex patterns of metabolic relationships. Based on the results, biological implications of metabolic changes were elucidated and discussed. Last, the results were further confirmed with our previous study (phenotype and gene expression results) using the same set of samples. Our finding provides in-depth information on altered amino acid metabolism and mechanisms in laying hens upon multiple Eimeria species infection.

Supplemental L-arginine promotes hepatocyte proliferation and alters liver fatty acid metabolism in the late embryonic phase: an RNA-seq analysis

The in ovo feeding (IOF) of L-arginine (L-Arg) to chick embryos is a viable method for improving early intestinal development, subsequently leading to an acceleration in growth rate during the posthatch stage. However, the liver, being the pivotal organ for energy metabolism in poultry, the precise effects and mechanisms of L-Arg on the liver development and metabolism remain unclear. To elucidate these, the present study injected 2 doses of L-Arg (10 mg/egg and 15 mg/egg) into the embryos of Hongyao chickens at 17.5 d of incubation, subsequently incubating them until d 19 for further analysis. IOF of 15 mg L-Arg/egg significantly increased the organ indices of liver and small intestine, as well as the duodenal villus height/crypt depth. RNA-Seq analysis of liver tissues showed that the metabolism of xenobiotics, amino acid metabolism, and the fatty acid metabolism were significantly enriched in L-Arg injection group. The core differentially expressed genes (DEGs) were primarily involved in cell proliferation and fatty acid metabolism. The CCK8 assays revealed that supplemental L-Arg significantly enhanced the proliferation of primary embryo hepatocytes and leghorn male hepatoma (LMH) cells. Upregulation of core DEGs, including HBEGF, HES4, NEK3, EGR1, and USP2, significantly promoted the proliferation of liver cells. Additionally, analysis of triglyceride and total cholesterol content, as well as oil red O staining, indicated that supplemental L-Arg effectively reduced lipid accumulation. Overall, L-Arg supplementation in late chick embryos may promote early liver and small intestine development by reducing liver lipid deposition and enhancing energy efficiency, necessitating further experimental validation. This study provides profound insights into the molecular regulatory network of L-Arg in promoting the development of chicken embryos. The identified DEGs that promote cell proliferation and lipid metabolism can serve as novel targets for further developing methods to enhance early development of chicken embryos.

Impact of dietary arginine supplementation on immune responses and growth performance in Newcastle disease virus-infected broiler chicks

BACKGROUND

Newcastle disease (ND) poses significant challenges within the poultry industry, leading to increased mortality rates, compromised growth, weakened immunity and elevated levels of inflammation.

OBJECTIVE

This study explores the potential of dietary arginine supplementation to ameliorate these adverse effects of ND, leveraging arginine's well-documented benefits in enhancing growth and immune responses.

METHODS

A total of 480 one-day-old male broiler chicks were meticulously categorised into eight groups, encompassing both infected and noninfected cohorts. These chicks received diets with arginine levels at 85%, 100%, 125% and 150% of recommended standards. The study entailed a comprehensive examination of clinical manifestations, growth performance metrics, haemagglutination inhibition (HI) test results, and serum concentrations of proinflammatory cytokines, adrenocorticotropic hormone (ACTH), and cortisol (CORT).

RESULTS

The infection significantly curtailed feed consumption (p = 0.0001) and weight gain (p = 0.0001) while concurrently depressing HI titres. Additionally, infected chicks experienced an exacerbated feed conversion ratio (p = 0.0001), escalated mortality rates (p = 0.0001), and elevated serum concentrations of proinflammatory cytokines (p = 0.0001), ACTH (p = 0.0001), and CORT (p = 0.0001). Remarkably, dietary arginine supplementation effectively mitigated the adverse impacts of ND infection on growth, immune responses and proinflammatory cytokine levels. In the context of ND infection, mortality rates and inflammation surge, while growth and immunity are significantly compromised.

CONCLUSIONS

The strategic inclusion of arginine in the diet emerges as a potent strategy to counteract the deleterious effects of ND. Supplementation with arginine at levels exceeding the conventional dietary recommendations is recommended to alleviate the detrimental consequences of ND effectively.

Effects of methionine supplementation in a reduced protein diet on growth performance, oxidative status, intestinal health, oocyst shedding, and methionine and folate metabolism in broilers under Eimeria challenge

BACKGROUND

This study investigated effects of different methionine (Met) supplementation levels in a reduced protein diet on growth performance, intestinal health, and different physiological parameters in broilers under Eimeria challenge. A total of 600 fourteen-day-old Cobb500 male broilers were challenged with E. maxima, E. tenella, and E. acervulina, and randomly allocated in a 2 × 5 factorial arrangement. Birds received normal protein diets (20% crude protein, NCP) or reduced protein diets (17% crude protein, LCP), containing 2.8, 4.4, 6.0, 7.6, and 9.2 g/kg of Met.

RESULTS

On 6 and 9 days post inoculation (DPI), increasing Met level linearly improved the growth performance (P < 0.05). Total oocyst shedding linearly increased as Met level increased (P < 0.05). Duodenal villus height (VH):crypt depth (CD) in the LCP groups were higher on 6 DPI (P < 0.01) while lower on 9 DPI (P < 0.05) compared to the NCP groups. Jejunal CD and duodenal VH:CD changed quadratically as Met level increased (P < 0.05). On 6 DPI, liver glutathione (GSH) and glutathione disulfide (GSSG) linearly increased as Met level increased (P < 0.05). On 9 DPI, GSSG quadratically increased, whereas GSH:GSSG quadratically decreased as Met levels increased (P < 0.05). The expression of amino acid transporters linearly decreased as Met level increased (P < 0.05). The expression of zonula occludens 2 and claudin-1 linearly increased on 6 DPI whereas decreased on 9 DPI as Met level increased (P < 0.05). The expressions of cytokines were lower in the LCP groups than the NCP groups (P < 0.05). Interaction effects were found for the expression of IL-10 and TNFα on 6 DPI (P < 0.05), where it only changed quadratically in the NCP group as Met level increased. The expression of Met and folate metabolism genes were lower in the LCP groups than the NCP groups on 9 DPI (P < 0.05). The expression of these genes linearly or quadratically decreased as Met level increased (P < 0.05).

CONCLUSION

These results revealed the regulatory roles of Met in different physiological parameters including oxidative status, intestinal health, and nutrient metabolism in birds fed reduced protein diet and challenged with Eimeria.

Different methionine to cysteine supplementation ratios altered bone quality of broilers with or without Eimeria challenge assessed by dual energy X-ray absorptiometry and microtomography

Despite the acknowledged significance of nutrition in bone development, effects of methionine (Met) and cysteine (Cys) on bone quality remain under-researched, particularly during Eimeria challenge. We investigated the effects of different supplemental Met to Cys ratios (MCR) on bone quality of broilers under Eimeria challenge. A total of 720 fourteen-day old Cobb500 broilers were allocated into a 5 × 2 factorial arrangement. Five diets with Met and Cys supplemented at MCR of 100:0, 75:25, 50:50, 25:75, and 0:100 were fed to the birds with or without Eimeria challenge. Body composition was measured by dual energy x-ray absorptiometry, and the femur bone characteristics were assessed by microtomography. Data were analyzed by two-way ANOVA and orthogonal polynomial contrast. The results reaffirmed the detrimental effects of Eimeria challenge on bone quality. On 9 d post inoculation (DPI), significant interaction effects were found for whole body bone mineral content (BMC), lean tissue weight, and body weight (P < 0.05); in the nonchallenged group (NCG), these parameters linearly decreased as MCR decreased (P < 0.05). In the challenged group (CG), body weight and lean tissue weight were unaffected by MCR, and BMC linearly increased as MCR decreased (P < 0.05). For the cortical bone of femoral metaphysis on 6 DPI, bone mineral density (BMD) linearly increased as MCR decreased (P < 0.05). Bone volume to tissue volume ratio (BV/TV) in the CG linearly increased as MCR decreased (P < 0.05). On 9 DPI, BMC and TV linearly increased as MCR decreased (P < 0.05) in the NCG. BMD and BV/TV changed quadratically as MCR decreased (P < 0.05). For the trabecular bone of femoral metaphysis on 9 DPI, BV/TV, and trabecular number linearly increased as MCR decreased (P < 0.05) in the NCG. For the femoral diaphysis, BV, TV, BMC on 6 DPI, and BMD on 9 DPI linearly increased as MCR decreased (P < 0.05). In conclusion, this study showed that both Eimeria challenge and varying supplemental MCR could influence bone quality of broilers.

Abnormal Feather Phenotype Associated with a Fatal Stress Response and Unusual Tolerance to Human Contact in the Zebra Finch (Taeniopygia castanotis)

The zebra finch (Taeniopygia castanotis) is a songbird sold in the pet trade and commonly used in research. In this report, we describe a set of partially overlapping traits shared by 3 birds in 2 broods from the same nest box that included atypical morphologic, developmental, and behavioral characteristics. The most obvious feature of this novel phenotype was feathers exhibiting a clumped appearance, which was accompanied by slow growth, delayed expression of adult plumage traits, and tameness, which we define as a lack of escape response upon handling without behavioral indicators of stress such as rapid breathing. Surprisingly, these birds also displayed a fatal response to nonhuman stressors. In one brood, a male expressed all of these characteristics, 2 females were wild-type, and a male sibling expressed only a hyperactive stress response but was otherwise normal. This indicates that the stress response could be inherited independently of the other abnormalities found in the male nest mate. In a second brood, a male bearing the abnormal feather phenotype behaved similarly to the male in the first brood, supporting the possibility that tameness is genetically associated with the unusual feather phenotype. The 2 other male and 2 female nest mates from this brood were behaviorally and visually normal, although the females developed slowly. Although similar traits have appeared in the aviary previously, such as slow development and small size, these are the first cases documented in detail. This correlated suite of traits suggests a linkage among altered feather growth, developmental rate, and brain and/or physiologic traits influencing normal fear and stress responses in the zebra finch. Awareness and study of the mechanism(s) linking these traits by examination of underlying genetic or environmental factors will allow a better understanding of the relationship between physical and behavioral traits in domesticated laboratory animals.

Coccidiosis in Egg-Laying Hens and Potential Nutritional Strategies to Modulate Performance, Gut Health, and Immune Response

Avian coccidiosis, despite advancements in management, nutrition, genetics, and immunology, still remains the most impactful disease, imposing substantial economic losses to the poultry industry. Coccidiosis may strike any avian species, and it may be mild to severe, depending on the pathogenicity of Eimeria spp. and the number of oocysts ingested by the bird. Unlike broilers, low emphasis has been given to laying hens. Coccidiosis in laying hens damages the gastrointestinal tract and causes physiological changes, including oxidative stress, immunosuppression, and inflammatory changes, leading to reduced feed intake and a drastic drop in egg production. Several countries around the world have large numbers of hens raised in cage-free/free-range facilities, and coccidiosis has already become one of the many problems that producers have to face in the future. However, limited research has been conducted on egg-laying hens, and our understanding of the physiological changes following coccidiosis in hens relies heavily on studies conducted on broilers. The aim of this review is to summarize the effect of coccidiosis in laying hens to an extent and correlate it with the physiological changes that occur in broilers following coccidiosis. Additionally, this review tries to explore the nutritional strategies successfully used in broilers to mitigate the negative effects of coccidiosis in improving the gut health and performance of broilers and if they can be used in laying hens.

Antifungal Activities of L-Methionine and L-Arginine Treatment In Vitro and In Vivo against Botrytis cinerea

Gray mold caused by Botrytis cinerea is a common postharvest fungal disease in fruit and vegetables. The prevention and treatment of postharvest gray mold has been one of the hot research issues addressed by researchers. This study aimed to investigate the effect of L-methionine and L-arginine on Botrytis cinerea in vitro and on cherry tomato fruit. The results of the in vitro experiment showed that L-methionine and L-arginine had significant inhibitory effects on the mycelial growth and spore germination of Botrytis cinerea, and the inhibitory effects were enhanced with increasing L-methionine or L-arginine concentration. In addition, L-methionine and L-arginine treatment increased the leakage of Botrytis cinerea electrolytes, proteins and nucleic acids. The experiment involving propidium iodide staining and malondialdehyde content assay also confirmed that L-methionine and L-arginine treatment could lead to cell membrane rupture and lipid peroxidation. The results of scanning electron microscopy further verified that the morphology of hyphae was damaged, deformed, dented and wrinkled after treatment with L-methionine or L-arginine. Fruit inoculation experiments displayed that L-methionine and L-arginine treatments significantly inhibited the occurrence and development of gray mold in postharvest cherry tomato. Therefore, treatment with L-methionine or L-arginine might be an effective means to control postharvest gray mold in fruit and vegetables.

Impacts of varying methionine to cysteine supplementation ratios on growth performance, oxidative status, intestinal health, and gene expression of immune response and methionine metabolism in broilers under Eimeria spp. challenge

A study was conducted to investigate effects of different methionine (Met) to cysteine (Cys) supplementation ratios (MCR) on growth performance, oxidative status, intestinal health, immune responses, and methionine metabolism in broilers under Eimeria challenge. A total of 720 male Cobb500 broilers (14-day-old) were allocated in a 2 × 5 factorial arrangement (5 diets, with or without challenge) with 6 replicates per treatment. The total sulfur amino acid concentrations were consistent across treatments meeting the breeder's recommendation, only MCR varied. The diets were labeled as MET100; MET75; MET50; MET25; and MET0, representing MCR of 100:0; 75:25; 50:50; 25:75; and 0:100, respectively. Data were analyzed by 2-way ANOVA and orthogonal polynomial contrast. Growth performance declined linearly or quadratically as MCR decreased (P < 0.01). On 6-day postinoculation (DPI), interaction effects (P < 0.01) were found; BW and body weight gain were lower in MET0 compared to the other treatments in the nonchallenged groups, whereas not in the challenged groups. On 6 and 9 DPI, serum total antioxidant capacity linearly decreased as MCR decreased (P < 0.05). Hepatic activities of glutathione peroxidase on 6 DPI and superoxide dismutase on 9 DPI changed quadratically as MCR decreased (P < 0.05). The digestibility of Met linearly decreased whereas the digestibility of Cys linearly increased as MCR decreased. The ileal crypt depth linearly decreased as MCR decreased (P < 0.01) on 6 DPI. The expression of transforming growth factor beta on 6 and 9 DPI, tumor necrotic factor alpha and interleukin 10 on 9 DPI changed quadratically as MCR decreased (P < 0.05). Eimeria challenge increased expression of Met adenosyltransferase and cystathionine gamma-lyase, whereas decreasing the expression of other Met metabolism genes (P < 0.01) on 6 DPI. Expression of Met metabolism genes linearly increased as MCR decreased (P < 0.05). In conclusion, different Met to Cys supplementation ratios exerted linearly or quadratically effects on the growth performance, oxidative status, intestinal health, and metabolism of Met in broiler chickens under Eimeria infection.

The effect of epigallocatechin gallate on laying performance, egg quality, immune status, antioxidant capacity, and hepatic metabolome of laying ducks reared in high temperature condition

Epigallocatechin gallate (EGCG) is a main component in green tea extract, which possesses multiple bioactivities. The present research studied the effects of EGCG on the laying performance, egg quality, immune status, antioxidant capacity, and hepatic metabolome of Linwu laying ducks reared under high temperature. A total of 180 42-w-old healthy Linwu laying ducks were allocated into control or EGCG-treated groups. Each treatment had 6 replicates with 15 ducks in each replicate. Diets for the two groups were basal diets supplemented with 0 or 300 mg/kg EGCG, respectively. All ducks were raised in the high temperature condition (35 ± 2 °C for 6 h from 10:00 to 16:00, and 28 ± 2 °C for the other 18 h from 16:00 to 10:00 the next day) for 21 days. Results showed that EGCG increased the egg production rate (p = 0.014) and enhanced the immunocompetence by improving serum levels of immunoglobulin A (p = 0.008) and immunoglobulin G (p = 0.006). EGCG also fortified the antioxidant capacity by activating superoxide dismutase (p = 0.012), catalase (p = 0.009), and glutathione peroxidase (p = 0.021), and increasing the level of heat-shock protein 70 (p = 0.003) in laying ducks' liver. At the same time, hepatic metabolomics result suggested that EGCG increased the concentration of several key metabolites, such as spermidine (p = 0.031), tetramethylenediamine (p = 0.009), hyoscyamine (p = 0.026), β-nicotinamide adenine dinucleotide phosphate (p = 0.038), and pantothenic acid (p = 0.010), which were involved in the metabolic pathways of glutathione metabolism, arginine and proline metabolism, β-alanine metabolism, and tropane, piperidine, and pyridine alkaloid biosynthesis. In conclusion, 300 mg/kg dietary EGCG showed protection effects on the laying ducks reared in high temperature by improving the immune and antioxidant capacities, which contributed to the increase of laying performance of ducks. The potential mechanism could be that EGCG modulate the synthesis of key metabolites and associated metabolic pathways.

The Functional Roles of Methionine and Arginine in Intestinal and Bone Health of Poultry: Review

This review explores the roles of methionine and arginine in promoting the well-being of poultry, with a specific focus on their impacts on intestinal and bone health. The metabolic pathways of methionine and arginine are elucidated, highlighting their distinct routes within the avian system. Beyond their fundamental importance in protein synthesis, methionine and arginine also exert their functional roles through their antioxidant capacities, immunomodulating effects, and involvement in the synthesis of metabolically important molecules such as S-adenosylmethionine, nitric oxide, and polyamines. These multifaceted actions enable methionine and arginine to influence various aspects of intestinal health such as maintaining the integrity of the intestinal barrier, regulating immune responses, and even influencing the composition of the gut microbiota. Additionally, they could play a pivotal role in promoting bone development and regulating bone remodeling, ultimately fostering optimal bone health. In conclusion, this review provides a comprehensive understanding of the potential roles of methionine and arginine in intestinal and bone health in poultry, thereby contributing to advancing the nutrition, overall health, and productivity of poultry in a sustainable manner.

The influence of dietary crude protein concentrations, grain types and arginine:lysine ratios on the performance of broiler chickens

The objective of this study was to investigate the effects of dietary crude protein (CP) concentrations, grain types and arginine:lysine ratios on performance parameters of broiler chickens. The 2 × 2 × 2 factorial array of dietary treatments harnessed two CP concentrations (210 and 170 g/kg), two feed grains (wheat and sorghum), and two arginine:lysine ratios (104 and 110). Each dietary treatment was offered to 7 replicates of 14 birds per floor pen, a total of 784 off-sex male, Ross 308 broilers, from 14 to 35 d post-hatch. The dietary CP reduction compromised weight gain by 10.0% (2078 versus 2310 g/bird) as a main effect and FCR by 7.51% (1.474 versus 1.371), subject to an interaction. In a three-way interaction (P = 0.008), expanded arginine:lysine ratios improved FCR by 2.30% in 170 g/kg CP, sorghum-based diets but compromised FCR by 2.12% in corresponding wheat-based diets. Sorghum was the more suitable feed grain in reduced-CP diets as sorghum generated significant advantages in weight gain of 7.59% (2154 versus 2002 g/kg) and FCR of 6.94% (1.421 versus 1.527) in birds offered 170 g/kg CP diets. Both dietary CP and feed grain generated significant and divergent impacts in apparent ileal digestibility coefficients for the majority of 16 assessed amino acids. Dietary CP reductions increased non-bound amino acid inclusions (NBAA) in wheat-based diets (48.96 versus 9.80 g/kg) to a greater extent than sorghum-based diets (35.3 versus 9.50 g/kg) and increasing dietary NBAA inclusions were linearly associated with compromised weight gain (r = -0.834; P < 0.001) and FCR (r = 0.862; P < 0.001). Increasing ratios of free arginine to lysine plasma concentrations were linearly (r = -0.466; P = 0.004) related to improvements in FCR. The implications of the observed outcomes are discussed and possible explanations are advanced.

Evaluation of the digestibility and antioxidant activity of protein and lipid after mixing nuts based on in vitro and in vivo models

This study aimed to evaluate the change of digestibility and antioxidant activity of protein and lipid after mixing walnuts, cashews, and pistachios using in vitro and in vivo models. The results showed that mixed nuts significantly reduced the digested particle size and the degree of hydrolysis of protein and triacylglycerol compared to single nuts in vitro. As a consequence of co-digestion, bioaccessibility and antioxidant activity for amino acids and fatty acids were increased by 1.12-1.87 fold and 1.62-3.81 fold, respectively. In vivo studies, the mixed nuts diet increased the concentration of amino acids and fatty acids in the small intestine by 27.69%-158.26% and 18.13%-152.09%, respectively, and enhanced levels of antioxidant enzymes in the liver and serum, all without causing weight gain. These findings highlight the positive interaction between single and mixed nuts, where mixed nuts enhanced the digestibility and antioxidant activity of single nuts both in vitro and in vivo.

Metabolic and microbiota response to arginine supplementation and cyclic heat stress in broiler chickens

Little attention has been paid to the biological role of arginine and its dietary supplementation in broilers under heat stress (HS) conditions. Therefore, the main aim of this study was to assess the response of broilers to arginine supplementation and cyclic HS, with a focus on liver, pectoral muscle, and blood metabolic profiles and the cecal microbiota. Day-old male Ross 308 broilers (n = 240) were placed in 2 rooms with 12 pens each for a 44-day trial. Pens were assigned to one of two groups (6 pens/group/room): the control group (CON) was given a basal diet in mash form and the treated group (ARG) was fed CON diet supplemented with crystalline L-arginine. The total arginine:lysine ratio of CON diet ranged between 1.02 and 1.07, while that of ARG diet was 1.20. One room was constantly kept at thermoneutral (TN) conditions, while the birds in the other room were kept at TN conditions until D34 and subjected to cyclic HS from D35 onwards (∼34°C; 9:00 A.M.–6:00 P.M.). Blood, liver, Pectoralis major muscle, and cecal content were taken from 2 birds per pen (12 birds/group/room) for metabolomics and microbiota analysis. Growth performance data were also collected on a pen basis. Arginine supplementation failed to reduce the adverse effects of HS on growth performance. Supplemented birds showed increased levels of arginine and creatine in plasma, liver, and P. major and methionine in liver, and reduced levels of glutamine in plasma, liver, and P. major. HS altered bioenergetic processes (increased levels of AMP and reduced levels of fumarate, succinate, and UDP), protein metabolism (increased protein breakdown to supply the liver with amino acids for energy production), and promoted the accumulation of antioxidant and protective molecules (histidine-containing dipeptides, beta-alanine, and choline), especially in P. major. Arginine supplementation may have partially counterbalanced the effects of HS on energy homeostasis by increasing creatine levels and attenuating the increase in AMP levels, particularly in P. major. It also significantly reduced cecal observed diversity, while HS increased alpha diversity indices and affected beta diversity. Results of taxonomic analysis at the phylum and family level are also provided.

Feeding broiler chickens with arginine above recommended levels: effects on growth performance, metabolism, and intestinal microbiota

BACKGROUND

Arginine is an essential amino acid for chickens and feeding diets with arginine beyond the recommended levels has been shown to influence the growth performance of broiler chickens in a positive way. Nonetheless, further research is required to understand how arginine supplementation above the widely adopted dosages affects metabolism and intestinal health of broilers. Therefore, this study was designed to assess the effects of arginine supplementation (i.e., total arginine to total lysine ratio of 1.20 instead of 1.06-1.08 recommended by the breeding company) on growth performance of broiler chickens and to explore its impacts on the hepatic and blood metabolic profiles, as well as on the intestinal microbiota. For this purpose, 630 one-day-old male Ross 308 broiler chicks were assigned to 2 treatments (7 replicates each) fed a control diet or a crystalline L-arginine-supplemented diet for 49 d.

RESULTS

Compared to control birds, those supplemented with arginine performed significantly better exhibiting greater final body weight at D49 (3778 vs. 3937 g; P < 0.001), higher growth rate (76.15 vs. 79.46 g of body weight gained daily; P < 0.001), and lower cumulative feed conversion ratio (1.808 vs. 1.732; P < 0.05). Plasma concentrations of arginine, betaine, histidine, and creatine were greater in supplemented birds than in their control counterparts, as were those of creatine, leucine and other essential amino acids at the hepatic level. In contrast, leucine concentration was lower in the caecal content of supplemented birds. Reduced alpha diversity and relative abundance of Firmicutes and Proteobacteria (specifically Escherichia coli), as well as increased abundance of Bacteroidetes and Lactobacillus salivarius were found in the caecal content of supplemented birds.

CONCLUSIONS

The improvement in growth performance corroborates the advantages of supplementing arginine in broiler nutrition. It can be hypothesized that the performance enhancement found in this study is associated with the increased availability of arginine, betaine, histidine, and creatine in plasma and the liver, as well as to the ability of extra dietary arginine to potentially ameliorate intestinal conditions and microbiota of supplemented birds. However, the latter promising property, along with other research questions raised by this study, deserve further investigations.

Comparative Analysis of the Temporal Impacts of Corticosterone and Simulated Production Stressors on the Metabolome of Broiler Chickens

The impact of physiological stress on the metabolome of breast muscle, liver, kidney, and hippocampus was investigated in Ross 308 broiler chicks. Simulated on-farm stressors were compared to a corticosterone model of physiological stress. The three different stressors investigated were: (i) corticosterone at a dose of 15 mg/kg of feed; (ii) heat treatment of 36 °C and 40% RH for 8 h per day; and (iii) isolation for 1 h per day. Liver, kidney, breast muscle, and hippocampus samples were taken after 2, 4, 6, and 8 days of stress treatment, and subjected to untargeted ¹H-nuclear magnetic resonance (NMR) spectroscopy-based metabolomic analysis to provide insights on how stress can modulate metabolite profiles and biomarker discovery. Many of the metabolites that were significantly altered in tissues were amino acids, with glycine and alanine showing promise as candidate biomarkers of stress. Corticosterone was shown to significantly alter alanine, aspartate, and glutamate metabolism in the liver, breast, and hippocampus, while isolation altered the same pathways, but only in the kidneys and hippocampus. Isolation also significantly altered the glycine, serine, and threonine metabolism pathway in the liver and breast, while the same pathway was significantly altered by heat in the liver, kidneys, and hippocampus. The study's findings support corticosterone as a model of stress. Moreover, a number of potential metabolite biomarkers were identified in chicken tissues, which may allow producers to effectively monitor stress and to objectively develop and evaluate on-farm mitigations, including practices that reduce stress and enhance bird health.

Functional properties of amino acids: improve health status and sustainability

The combination of increased genetic potential and changes in management strategies (i.e., antibiotic-free, no antibiotics ever, and every day feeding of replacement pullets) influences the nutritional needs of poultry. Traditionally, nutritionists have focused on meeting the amino acid needs for production performance and yield however, increasing specific amino acid concentrations can benefit gastrointestinal development and integrity, enhance immune response potential, influence behavior, and benefit sustainability. Commercialization of additional feed grade amino acids beyond methionine, lysine, and threonine, enables targeted increases to achieve these benefits. As such, this paper addresses the functional roles of amino acids in meeting poultry production, health, and sustainability goals.

Cannabidiol and Nano-Selenium Increase Microvascularization and Reduce Degenerative Changes in Superficial Breast Muscle in C. perfringens-Infected Chickens

Here, we demonstrated the potential of Cannabis-derived cannabidiol (CBD) and nanosized selenium (nano-Se) for the modulation of microvascularization and muscle fiber lesions in superficial breast muscle in C. perfringens-challenged chickens. The administration of CBD resulted in a decreased number of atrophic fibers (3.13 vs. 1.13/1.5 mm²) compared with the control, whereas nano-Se or both substances resulted in a decreased split fiber number (4.13 vs. 1.55/1.5 mm²) and in a lower number of necrotic myofibers (2.38 vs. 0.69/1.5 mm²) in breast muscle than the positive control. There was a significantly higher number of capillary vessels in chickens in the CBD+Nano-Se group than in the control and positive control groups (1.31 vs. 0.97 and 0.98, respectively). Feeding birds experimental diets lowered the activity of DNA damage repair enzymes, including 3,N4-ethenodeoxycytosine (by 39.6%), 1,N6-ethenodeoxyadenosine (by 37.5%), 8-oxo-guanine (by 36.2%), formamidopyrimidine (fapy)-DNA glycosylase (by 56.2%) and human alkyl adenine DNA glycosylase (by 40.2%) in the ileal mucosa, but it did not compromise the blood mitochondrial oxygen consumption rate (-2.67 OD/min on average). These findings indicate a potential link between gut mucosa condition and histopathological changes in superficial pectoral muscle under induced inflammation and show the ameliorative effect of CBD and nano-Se in this cross-talk due to their protection from mucosal DNA damage.

Additional supplementation of sulfur-containing amino acids in the diets improves the intestinal health of turbot fed high-lipid diets

An eight-week feeding trial was conducted to investigate the effects of diets supplemented with three sulfur-containing amino acids (SAA), namely, methionine, cysteine, and taurine, on the intestinal health status of juvenile turbot (Scophthalmus maximus) fed high-lipid diets. Four diets were formulated, namely, a high-lipid control diet (16% lipid, HL) and three SAA-supplemented diets, which were formulated by supplementing 1.5% methionine (HLM), 1.5% cysteine (HLC), and 1.5% taurine (HLT) into the HL control diet, respectively. Each diet was assigned to triplicate tanks, and each tank was stocked with 30 juvenile fish (appr. initial weight, 8 g). The histological and morphometric results showed that dietary SAA supplementation obviously improved the intestinal morphology and integrity, in particular as reflected by higher height of microvilli and mucosal folds. Dietary SAA supplementation, in particular cysteine, up-regulated the gene expression of mucin-2 and tight junction proteins (ZO-1, Tricellilun and JAM). Dietary SAA supplementation remarkably down-regulated the gene expression of apoptosis-related factors such as p38, JNK, and Bax, expression of pro-inflammatory factors (e.g., NF-κB, AP-1 IL-1β, IL-8, and TNF-α). SAA supplementation resulted in higher antioxidative abilities in the intestine. Additionally, dietary SAA supplementation largely altered the communities of intestinal microbiota. Compared with the HL group, higher relative abundance of potential beneficial bacteria, and lower relative abundance of opportunistic pathogens were observed in SAA-supplemented groups. Dietary taurine supplementation significantly increased the relative abundance of Ligilactobacillus (in particular Lactobacillus murinus) and Limosilactobacillus (especially Lactobacillus reuteri). In conclusion, dietary sulfur-containing amino acids supplementation have promising potential in ameliorating the intestinal inflammation of turbot fed high-lipid diets. Especially dietary cysteine and taurine supplementation have more positive effects on the communities of the intestinal microbiota of turbot.

The Sarcoplasmic Protein Profile of Breast Muscle in Turkeys in Response to Different Dietary Ratios of Limiting Amino Acids and Clostridium perfringens-Induced Inflammation

In this study, the effects of the Arginine/Lysine (Arg/Lys) ratio in low- and high-methionine (Met) diets on the sarcoplasmic protein profile of breast muscles from turkeys reared under optimal or challenge (Clostridium perfringens infection) conditions were determined. One-day-old Hybrid Converter female turkey poults (216 in total) obtained from a commercial hatchery on hatching day, and on the basis of their average initial body weight were randomly allocated to 12 pens (4 m² each; 2.0 m × 2.0 m) containing litter bedding and were reared over a 42-day experimental period. Diets with high levels of Lys contained approximately 1.80% and 1.65% Lys and were offered in two successive feeding periods (days 1–28 and days 29–42). The supplemental levels of Lys were consistent with the nutritional specifications for birds at their respective ages as established in the Management Guidelines for Raising Commercial Turkeys. The experiment was based on a completely randomized 3 × 2 × 2 factorial design with three levels of Arg (90%, 100% and 110%) relative to the content of dietary Met (30 or 45%) and without (−) or with (+) C. perfringens challenge at 34, 36, or 37 d of age. Meat samples were investigated in terms of pH, color, and sarcoplasmic protein profile. The experimental factors did not influence meat quality but the dietary Arg content affected meat color. The sarcoplasmic protein profile was influenced by all studied factors, and glycolytic enzymes were the most abundant. This study evidenced strong association between the challenge conditions and the involvement of glycolytic enzymes in cell metabolism, particularly in inflammatory processes, and DNA replication and maintenance in turkeys. The results showed an effect of C. perfringens infection and feeding with different doses of Arg and Met may lead to significant consequences in cell metabolism.

A review of heat stress in chickens. Part II: Insights into protein and energy utilization and feeding

With the growing global demand for animal protein and rising temperatures caused by climate change, heat stress (HS) is one of the main emerging environmental challenges for the poultry industry. Commercially-reared birds are particularly sensitive to hot temperatures, so adopting production systems that mitigate the adverse effects of HS on bird performance is essential and requires a holistic approach. Feeding and nutrition can play important roles in limiting the heat load on birds; therefore, this review aims to describe the effects of HS on feed intake (FI) and nutrient digestibility and to highlight feeding strategies and nutritional solutions to potentially mitigate some of the deleterious effects of HS on broiler chickens. The reduction of FI is one of the main behavioral changes induced by hot temperatures as birds attempt to limit heat production associated with the digestion, absorption, and metabolism of nutrients. Although the intensity and length of the heat period influences the type and magnitude of responses, reduced FI explains most of the performance degradation observed in HS broilers, while reduced nutrient digestibility appears to only explain a small proportion of impaired feed efficiency following HS. Targeted feeding strategies, including feed restriction and withdrawal, dual feeding, and wet feeding, have showed some promising results under hot temperatures, but these can be difficult to implement in intensive rearing systems. Concerning diet composition, feeding increased nutrient and energy diets can potentially compensate for decreased FI during HS. Indeed, high energy and high crude protein diets have both been shown to improve bird performance under HS conditions. Specifically, positive results may be obtained with increased added fat concentrations since lipids have a lower thermogenic effect compared to proteins and carbohydrates. Moreover, increased supplementation of some essential amino acids can help support increased amino acid requirements for maintenance functions caused by HS. Further research to better characterize and advance these nutritional strategies will help establish economically viable solutions to enhance productivity, health, welfare, and meat quality of broilers facing HS.

Effects of DL and L-Methionine on Growth Rate, Feather Growth, and Hematological Parameters of Tetra-SL Layers from 1-28 Days of Age

The study was carried out to determine whether sources or levels of methionine (Met) affect the health status of Tetra-SL (TSL) chicks by examining growth performance, feather growth, and hematological parameters. A total of ninety-six (96) day-old (44.2 ± 0.18 g lw) TSL chicks were randomly allotted to six treatment groups (three levels for each DL and L-Met source) with four replicates of four chicks each. Chicks were fed ad libitum diets supplemented with 90, 100, and 110% of methionine requirements for four weeks after hatch. The parameters examined are bodyweight (BW), average daily gain (ADG), feather length (FL), and hematological parameters, including: red blood cell (RBC) count, hemoglobin (Hb) concentration in the blood, hematocrit (Ht; %), number of white blood cells (WBC), platelet count, mean corpuscular volume of red blood cells (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), lymphocyte (LYM), mid-range (MID), and granulocyte (GRAN). There was no significant effect of Met sources and levels on BW, ADG, and FL of TSL chicks for the first four weeks of rearing. The RBC, Hb, Ht, WBC, LYM, MID, and GRAN values of TSL chicks were statistically influenced by dietary Met sources and Met levels (p < 0.05). Among the treatment groups, the number of white blood cells (WBC) on 90% DL−Met was the lowest. WBC, RBC, Hb, and Ht were higher from chicks that received 100% DL-Met than all other levels, regardless of the Met sources. The MCV, MCH, and MCHC values were not affected by either Met source or levels or their interactions. Met source and level interactively affected the Ht, WBC, LYM %, and GRAN values of TSL chicks (p < 0.05). The platelet number was affected by Met source only (p < 0.05) with chicks receiving L-Met source having more than twofold higher platelet values than DL-Met source. In conclusion, varying Met levels by ±10% of the requirement does not adversely affect the growth performance, feather growth, and hematological parameters of TSL chicks reared for up to four weeks of age. DL-Met increased the body weight and improved the white blood cells, red blood cells, and hematocrit at 28 days after hatch. DL-Met showed similar biological efficacy as L-Met for body weight and feather growth but not for the hematological parameters.

Influence of dietary L-carnitine and lysine-methionine levels on reproductive performance and blood metabolic constituents of breeder ducks

The present study aimed to evaluate the influence of dietary supplementation of different levels of L-carnitine and/or lysine-methionine (Lys-Met) on reproductive performance of breeder ducks. Three L-carnitine (0, 75 and 150 mg/kg) and three lysine-methionine (100%, 110% and 120% above the NRC (Nutrient requirements of poultry, 1994, National Academy Press) recommendations) levels were fed to 180 breeder ducks (144 females and 36 males) in a completely randomized design for 49 days. Laying performance and reproductive traits were evaluated; additionally, uric acid, total protein total, triglycerides, total cholesterol, low-density lipoprotein, high-density lipoprotein, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were assessed. The Lys-Met above 100% NRC (Nutrient requirements of poultry, 1994, National Academy Press) recommendations with or without L-carnitine improved feed utilization (p < .05). Furthermore, Lys-Met above 100% recommendations without L-carnitine improved egg fertility and hatchability. Fertility and hatchability improved in breeders fed on L-carnitine with 120% Lys-Met (p < .05). Serum glucose increased and total cholesterol reduced on 100% Ly-Met without L-carnitine or 110% Ly-Met with 150 mg L-carnitine (p < .05). Glucose was reduced, while total cholesterol increased on 75 mg L-carnitine and 100% Lys-Met (p < .05). Increasing Lys-Met without L-carnitine reduced serum protein (p < .05). Albumin and ALT increased on 75 mg L-carnitine-100% Lys-Met and reduced on 150 mg L-carnitine-120% Lys-Met (p < .05). There were no interaction effects on globulin, uric acid and AST (p > .05). Thus, based on findings, breeder ducks responded to dietary Lys-Met more efficiently than L-carnitine; however, more research is needed to evaluate also economic aspects related to L-carnitine dietary supplementation.

Nutritional and Volatile Characterisation of Milk Inoculated with Thermo-Tolerant Lactobacillus bulgaricus through Adaptive Laboratory Evolution

In this study, thermo-tolerant strain of Lactobacillus bulgaricus (L. bulgaricus) was developed using gradual increase in temperature to induce Adaptive Laboratory Evolution (ALE). Viable colony count of 1.87 ± 0.98 log cfu/mL was achieved at 52 °C, using MRS agar supplemented with 2% lactose. Changes in bacteria morphology were discovered, from rod (control) to filament (52 °C) to cocci after frozen storage (−80 °C). When milk was inoculated with thermo-tolerant L. bulgaricus, lactic acid production was absent, leaving pH at 6.84 ± 0.13. This has caused weakening of the protein network, resulting in high whey separation and lower water-holding capacity (37.1 ± 0.35%) compared to the control (98.10 ± 0.60%). Significantly higher proteolytic activity was observed through free amino acids analysis by LC-MS. Arginine and methionine (237.24 ± 5.94 and 98.83 ± 1.78 µg/100 g, respectively) were found to be 115- and 275-fold higher than the control, contributing to changing the aroma similar to cheese. Further volatile analysis through SPME-GC-MS has confirmed significant increase in cheese-aroma volatiles compared to the control, with increase in diacetyl formation. Further work on DNA profiling, metabolomics and peptidomics will help to answer mechanisms behind the observed changes made in the study.

Effects of low-crude protein diets supplemented with arginine, glutamine, threonine, and methionine on regulating nutrient absorption, intestinal health, and growth performance of Eimeria-infected chickens

The study was conducted to evaluate the effects of low crude protein diets supplemented with arginine, glutamine, methionine, and/or threonine on apparent ileal digestibility of amino acids, intestinal morphology, intestinal permeability, gene expression of nutrient transporters, and tight junction proteins of broiler chickens challenged with mixed Eimeria spp. A total of five hundred seventy-six, 12-day-old male broiler chickens were allocated into 8 treatments, and 6 replicate cages of 12 chickens per cage. This experiment included a nonchallenged control (NC) fed regular corn-soybean meal-based diet (Regular diet, 19% crude protein), an Eimeria-challenged control (CC) fed Regular diet, an Eimeria challenge group fed low-crude protein diet (LCP, 16% crude protein), 4 Eimeria challenge groups fed low-crude protein diet supplemented with 0.75% arginine, glutamine, methionine, and threonine, respectively (ARG, GLN, MET, and THR), and an Eimeria challenge group fed low-crude protein diet with 0.75% supplemented arginine, glutamine, methionine, and threonine collectively as a combination group (COMB). On d 14, birds in the challenge groups were gavaged with a mixed Eimeria spp. solution containing 12,500 oocysts of E. maxima, 12,500 oocysts of E. tenella, and 62,500 oocysts of E. acervulina. The results showed that the Eimeria challenge reduced overall growth performance, but the LCP had no adverse impacts on intestinal health and growth of Eimeria-infected birds compared to the CC. Additionally, supplementation of crystalline arginine, glutamine, methionine, and threonine improved the apparent ileal digestibility of these specific amino acids on 6 dpi. Moreover, the THR treatment increased villus height in the duodenum. The ARG treatment decreased intestinal permeability and gene expression of amino acid transporters, whereas the GLN and THR treatments both reversed adverse effects of coccidiosis on gene expression of tight junction protein (claudin 1). However, the MET and COMB treatments exacerbated infection severity of coccidiosis. In summary, adding 0.75% of arginine, glutamine, or threonine in a low crude protein diet can improve the intestinal health of birds challenged with a mild coccidia infection.

Increased Dietary Inclusion Levels of Lysine Are More Effective than Arginine in Supporting the Functional Status of the Gut in Growing Turkeys

Arginine (Arg) and lysine (Lys) may be important for the overall health of turkeys. The aim of this study was to determine whether low (consistent with the guidelines) and high (10% higher than recommended) levels of dietary Arg and Lys can modulate performance and the functional status of the gut. Female turkeys were allocated to four dietary treatments (two levels of Lys (low or high) and two levels of Arg (low or high)) for a 16 wk feeding period. The treatments did not affect turkey performance determined separately for four feeding phases and for the entire 16 wk experiment (p > 0.05). They had no significant influence on carcass yield, meat characteristics or the associated traits either (p > 0.05). High-Lys diets contributed to a decrease in cecal pH, a significant increase in the concentrations of short-chain fatty acids (SCFA) and a decrease in the concentrations of putrefactive SCFA and ammonia in the cecum. High dietary levels of both amino acids significantly enhanced the activity of cecal microbiota evaluated based on extracellular enzyme activity. These findings indicate that the higher dietary level of Lys was more effective in modulating the physiological status of the gut in turkeys than Arg.

Impacts of increasing challenge with Eimeria maxima on the growth performance and gene expression of biomarkers associated with intestinal integrity and nutrient transporters

This study was conducted to investigate the impacts of graded severity of Eimeria maxima infection on the growth performance and intestine health of broiler chickens. Four different levels of E. maxima-challenged treatments were used, including a non-challenged control group, a low challenge (12 500 oocysts), a medium challenge (25 000 oocysts), and a high challenge dose (50 000 oocysts). There were eight replicate cages per treatment, with 12 birds in each cage, and chickens in the challenged groups orally received sporulated oocysts on day 14. Gastrointestinal permeability was measured by fluorescein isothiocyanate dextran at 5 days post-infection (dpi), whereas intestinal morphology and gene expression of nutrient transporters and tight junction proteins were determined at 6 dpi. The results demonstrate a linear reduction in growth performance, jejunal villus height, and jejunal integrity with graded challenge doses of E. maxima (P < 0.01). Moreover, linear regulation of nutrient transporters and tight junction proteins was a consequence of increasing Eimeria infection levels (P < 0.01). The linear increase of Claudin 1, cationic amino acid transporter, glucose transporter 1, and L-type amino acid transporter genes was associated with increased severity of coccidiosis (P < 0.01). Furthermore, expression of nutrient transporters located at the brush border membrane were down-regulated (P < 0.01) with increasing E. maxima inoculation dose. In conclusion, growth performance and key intestinal integrity biomarkers in broiler chickens were adversely influenced in a dose-dependent manner by E. maxima infection.