Nutritional consequences of interspecies differences in arginine and lysine metabolism

Phase-specific outcmes of arginine or branched-chain amino acids supplementation in low crude protein diets on performance, nutrient digestibility, and expression of tissue protein synthesis and degradation in broiler chickens infected with mixed Eimeria spp

A 35-d study investigated the impact of dietary supplementation with Arginine (Arg) or branched-chain amino acids (BCAA) of broilers receiving low-protein diets whilst infected with mixed Eimeria species. All birds were given the same starter (d0-10) and finisher (d28-35) diets. The 4 grower diets used were a positive control (PC) with adequate protein (18.5%), a low protein diet (NC;16.5% CP), or the NC supplemented with Arg or BCAA. Supplemental AA was added at 50% above the recommended levels. The treatments were in a 4 × 2 factorial arrangement, with 4 diets, with or without Eimeria inoculation on d14. Birds and feed were weighed after inoculation in phases: prepatent (d14-17), acute (d18-21), recovery (d22-28), and compensatory (d29-35). Ileal digesta, jejunum, and breast tissue were collected on d21, 28, and 35. There was no diet × Eimeria inoculation on growth performance at any phase. Infected birds weighed less and consumed less feed (P < 0.05) in all phases. In the prepatent and acute phases, birds on the Arg diets had higher weight gain (P < 0.05) and lower FCR, similar to PC, when compared to NC and BCAA-fed ones. Infection reduced AA digestibility on d21 and 28 (Met and Cys). However, birds that received supplemental AA had higher digestibility (P < 0.05) of their respective supplemented AA on d 21 only. Infected birds had lower (P < 0.05) BO + AT and higher PEPT1 expression on d21. There was a diet × Eimeria interaction (P = 0.004) on gene expression at d28; 4EBP1 genes were significantly downwardly expressed (P < 0.05) in birds fed Arg diet, irrespective of infection. Infected birds exhibited an upward expression (P < 0.05) of Eef2 on d21 and d28 but experienced a downward expression on d35. Supplemental Arg and BCAA had variable effects on growth performance, apparent ileal AA digestibility, and genes of protein synthesis and degradation, but the effect of Arg on promoting weight gain, irrespective of the Eimeria challenge, was more consistent.

Interactive effects of dietary leucine and isoleucine affect amino acid profile and metabolism through AKT/TOR signaling pathways in blunt snout bream (Megalobrama amblycephala)

The purpose of this research is to explore the interaction between dietary leucine and isoleucine levels on whole-body composition, plasma and liver biochemical indexes, amino acids deposition in the liver, and amino acid metabolism of blunt snout bream (Megalobrama amblycephala). The test fish (average weight: 56.00 ± 0.55 g) were fed one of six diets at random containing two leucine levels (1.70% and 2.50%) and three isoleucine levels (1.00%, 1.20%, and 1.40%) for 8 weeks. The results showed that the final weight and weight gain rate were the highest in the fish fed low-level leucine and high-level isoleucine diets (P > 0.05). Furthermore, the crude lipid content was significantly adjusted by diets with diverse levels of leucine and isoleucine (P < 0.05). In addition, interactive effects of these two branched-chain amino acids (BCAAs) were found on plasma total protein, blood ammonia, and blood urea nitrogen of test fish (P < 0.05). Additionally, the liver amino acid profiles were significantly influenced by the interactive effects of the two BCAAs (P < 0.05). Moreover, interactive effects of dietary leucine and isoleucine were significantly observed in the expressions of amino acid metabolism-related genes (P < 0.05). These findings suggested that dietary leucine and isoleucine had interaction. Meanwhile, the interaction between them was more conducive to the growth and quality improvement of blunt snout bream when the dietary leucine level was 1.70% and isoleucine level was 1.40%.

Beyond protein synthesis: the emerging role of arginine in poultry nutrition and host-microbe interactions

Arginine is a functional amino acid essential for various physiological processes in poultry. The dietary essentiality of arginine in poultry stems from the absence of the enzyme carbamoyl phosphate synthase-I. The specific requirement for arginine in poultry varies based on several factors, such as age, dietary factors, and physiological status. Additionally, arginine absorption and utilization are also influenced by the presence of antagonists. However, dietary interventions can mitigate the effect of these factors affecting arginine utilization. In poultry, arginine is utilized by four enzymes, namely, inducible nitric oxide synthase arginase, arginine decarboxylase and arginine: glycine amidinotransferase (AGAT). The intermediates and products of arginine metabolism by these enzymes mediate the different physiological functions of arginine in poultry. The most studied function of arginine in humans, as well as poultry, is its role in immune response. Arginine exerts immunomodulatory functions primarily through the metabolites nitric oxide (NO), ornithine, citrulline, and polyamines, which take part in inflammation or the resolution of inflammation. These properties of arginine and arginine metabolites potentiate its use as a nutraceutical to prevent the incidence of enteric diseases in poultry. Furthermore, arginine is utilized by the poultry gut microbiota, the metabolites of which might have important implications for gut microbial composition, immune regulation, metabolism, and overall host health. This comprehensive review provides insights into the multifaceted roles of arginine and arginine metabolites in poultry nutrition and wellbeing, with particular emphasis on the potential of arginine in immune regulation and microbial homeostasis in poultry.

Shuttle between arginine and lysine: influence on cancer immunonutrition

Amino acids which are essential nutrients for all cell types' survival are also recognised to serve as opportunistic/alternative fuels in cancers auxotrophic for specific amino acids. Accordingly, restriction of amino acids has been utilised as a therapeutic strategy in these cancers. Contrastingly, amino acid deficiencies in cancer are found to greatly impair immune functions, increasing mortality and morbidity rates. Dietary and supplemental amino acids in such conditions have revealed their importance as 'immunonutrients' by modulating cellular homeostasis processes and halting malignant progression. L-arginine specifically has attracted interest as an immunonutrient by acting as a nodal regulator of immune responses linked to carcinogenesis processes through its versatile signalling molecule, nitric oxide (NO). The quantum of NO generated directly influences the cytotoxic and cytostatic processes of cell cycle arrest, apoptosis, and senescence. However, L-lysine, a CAT transporter competitor for arginine effectively limits arginine input at high L-lysine concentrations by limiting arginine-mediated effects. The phenomenon of arginine-lysine antagonism can, therefore, be hypothesised to influence the immunonutritional effects exerted by arginine. The review highlights aspects of lysine's interference with arginine-mediated NO generation and its consequences on immunonutritional and anti-cancer effects, and discusses possible alternatives to manage the condition. However, further research that considers monitoring lysine levels in arginine immunonutritional therapy is essential to conclude the hypothesis.

Composition and contents of fatty acids and amino acids in the mycelia of Lentinula edodes

With the global shortages of animal protein foods, mycoprotein as a low-cost alternative source of protein by its high-protein and low-fat content has become a development trend. Lentinula edodes (L. edodes) is a healthy food with high protein and low fiber. This work evaluated the nutritional value of L. edodes mycelia, and determined the composition and contents of fatty acids and amino acids. Eleven saturated fatty acids (SFAs) and 12 unsaturated fatty acids (UFAs) were detected in the mycelia of L. edodes. The UFA content accounted for 75.7% and 73.1% of the total fatty acid content in the mycelia of strains 18 and 18N44, respectively. Linoleic acid was the major polyunsaturated fatty acid (PUFA) in the mycelia, accounting for 91.0% and 86.3% of the UFAs, respectively. The mycelia of the two strains contained 17 types of amino acids, and the essential amino acids were sufficient (357.92 ± 0.42 and 398.38 ± 4.52 mg/g pro, respectively), both close to the WHO/FAO reference protein pattern value. The most abundant essential amino acid was Lys, and the limiting amino acids were Met + Cys and Ile, respectively. The SRC values in the mycelia of the two strains were 68.07 and 54.86, and the EAAI values were 67.70 and 74.42, respectively, both being close to those of ovalbumin. It is concluded that L. edodes mycelia are rich in easily absorbed high-quality proteins and PUFAs, and can be used as a source for meat analog required by vegetarians. This study provides a scientific basis for the further utilization of mycelial resources.

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.

Effects of dietary supplementation of tomato pomace (Solanum lycopersicum L.) and L-Arg on reproductive performance of aged male broiler breeders

This study aimed to investigate the effects of different dietary supplementation of tomato pomace (TP) and L-arginine (L-Arg) supplementation on sperm characteristics, reproductive performance, and semen biochemical components of aged commercial male broiler breeders. Thirty Ross 308 male broiler breeders (58 wk old) were provided and assigned to 5 dietary treatment groups, including control (CON), 5% TP (TPS-5), 10% TP (TPS-10), 15% TP (TPS-15), and L-Arg supplemented (10% above the recommendation, LAS-10). The results indicated that the semen volume increased in the TPS-15 group compared to that of the LAS-10 (and CON on wk 9) throughout the study (P < 0.05). The sperm concentration significantly increased in TPS-10 and TPS-15 groups in comparison to the other experimental groups. On wk 5 and 7, the sperm viability increased in all TPS groups compared to the CON and LAS-10, while on wk 9, it only increased in the TPS-10 group in comparison to the LAS-10 group (P < 0.05). The hypo-osmotic swelling test decreased in the LAS-10 group compared to the other experimental groups on wk 5 and all TPS groups on wk 7 and 9 (P < 0.05). The sperm total motility and forward progressive motility decreased in the LAS-10 group compared to the other experimental groups (P < 0.05). In contrast, unprogressive motility and immotile sperms were increased in the LAS-10 group compared to the other experimental groups (P < 0.05). In addition, the sperm penetration and fertility rate increased in TPS-10 and TPS-15 groups in comparison to CON and LAS-10 groups (P < 0.05). However, hatchability was reduced in the LAS-10 group (P < 0.05). The semen adenosine triphosphate increased in TPS-10, TPS-15, and LAS-10 groups compared to the CON (P < 0.05). Finally, the semen TAC and superoxidase dismutase decreased in the LAS-10 group (P < 0.05), while the glutathione peroxidase increased in the TPS-15 group (P < 0.05). In conclusion, 15% dietary TPS is recommended to improve the reproductive performance of aged commercial male broiler breeders.

Dietary Isoleucine and Valine: Effects on Lipid Metabolism and Ureagenesis in Pigs Fed with Protein Restricted Diets

A mixture of valine (Val) and isoleucine (Ile) not only decreases the negative impact of very low protein (VLP) diets on the growth of pigs, but also influences the nitrogen (N) balance and lipid metabolism; however, the underlying pathways are not well understood. This study aimed to investigate the effect of dietary Val and Ile on lipogenesis, lipolysis, and ureagenesis under protein restriction. After one week of acclimation, forty three-week-old pigs were randomly assigned to following dietary treatments (n = 8/group) for 5 weeks: positive control (PC): normal protein diet; negative control (NC): VLP diet; HV: NC supplemented with Val; HI: NC supplemented with Ile; and HVI: NC supplemented with both Val and Ile. HVI partially improved the body weight and completely recovered the feed intake (FI) of pigs fed with NC. HVI increased thermal radiation and improved the glucose clearance. HVI had a lower blood triglyceride than PC and blood urea N than NC. NC and HV promoted lipogenesis by increasing the transcript of fatty acid synthase (FAS) in the liver and lipoprotein lipase (LPL) in adipose tissue but reducing hormone-sensitive lipase (HSL) in the liver. HVI reduced the increased rate of lipogenesis induced by the NC group through normalizing the mRNA abundance of hepatic FAS, sterol regulatory element binding transcription factor 1, and HSL and LPL in adipose tissue. NC, HV, HI, and HVI reduced the ureagenesis by decreasing the protein abundance of carbamoyl phosphate synthetase I, ornithine transcarboxylase, and arginosuccinate lyase in the liver. Overall, HVI improved the growth, FI, and glucose clearance, and decreased the rate of lipogenesis induced by VLP diets.

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.

Effects of branched-chain amino acids to lysine ratios in corn distillers dried grains with solubles containing diets on growth performance, plasma nitrogen profile, carcass traits, and economic analysis in growing-finishing pigs

A study was conducted to identify the effects of standardized ileal digestible (SID) branched-chain amino acids (BCAA):lysine (Lys) ratios on the growth performance, plasma nitrogen (N) profile, carcass traits, and economic analysis of growing-finishing pigs fed diets with high corn distillers dried grains with solubles (cDDGS) inclusions. A total of 1,140 pigs (initial body weight [BW] = 28.7 ± 2.0 kg) were housed in 45 pens of 25 or 26 pigs and fed one of five diets in a randomized complete block design. Experimental diets were fed in four phases based on BW. Dietary treatments were a corn-soybean meal (SBM) based diet (PC), a corn-SBM-cDDGS-based diet (NC) with SID BCAA:Lys ratio of PIC (2020) recommendation and NC diets with SID BCAA:Lys ratios targeted for the 73% SID Val:Lys, 60% SID Ile:Lys, and 144% SID Leu:Lys during the growing phases (25 to 80 kg, Grow), targeted for the 78% SID Val:Lys, 70% SID Ile:Lys, and 160% to 170% SID Leu:Lys during the finishing phases (80 to 120 kg, finish), and both during the growing and finishing phases (Grow-Finish). One pig from each pen was bled at the end of 7 and 13 wk. After the 11-wk-feeding trial, pigs were sent to a commercial abattoir to investigate carcass traits. Pigs fed the Finish diet had a greater overall average daily gain (P < 0.05) than pigs fed the other cDDGS diets. Dietary treatments did not affect the hot carcass weight. However, feeding the Finish diet increased (P < 0.05) the iodine value of pork belly samples and decreased (P < 0.05) carcass yield. The plasma urea nitrogen (PUN) concentration at the end of the growing phase and plasma concentrations of Leu and Val were greater (P < 0.05) in pigs fed the Finish diet compared to the other cDDGS diets. Feeding pigs the cDDGS diets with different BCAA:Lys ratios had no difference in income over feed cost and income over feed and facility costs compared to the corn-SBM diet. Therefore, feeding pigs cDDGS diets with SID BCAA:Lys ratios adjusted for the previously determined finishing phase (from 80 to 120 kg of BW) recommendations by SBM inclusion supported growth performance and economic benefits equal to the corn-SBM diet.

Optimal dietary standardized ileal digestible lysine level for pigs during the grower, early and late finisher periods

BACKGROUND

Lysine (Lys) is the first limiting amino acid for pigs fed corn-soybean meal diets. Three experiments were conducted to estimate the optimal standardized ileal digestible (SID) Lys requirement for growing (Exp. 1), early finishing (Exp. 2), and late finishing (Exp. 3) pigs under commercial conditions.

RESULTS AND CONCLUSIONS

In Exp. 1, a total of 650 growing pigs (32.21 ± 0.33 kg bodyweight), were allocated to 5 dietary treatments supplemented with 0.75, 0.85, 0.94, 1.03, and 1.13% SID Lys. Each treatment had 5 replicate pens with 26 pigs per pen. The lowest feed to gain ratio (F:G) was obtained by pigs fed the 1.03% Lys diet and F:G showed both a linear and a quadratic response with increasing Lys (P < 0.05). Based on broken-line and quadratic analysis models, dietary SID Lys levels for the minimum F:G were 0.94%. In Exp. 2, 650 finishing pigs (57.24 ± 2.00 kg bodyweight) were allotted to 5 dietary treatments providing SID Lys of 0.63, 0.71, 0.79, 0.87, and 0.95%. Each treatment had 5 replicates, 26 pigs per replication. The highest final bodyweight was achieved by 0.79% Lys while the highest average daily gain (ADG) and average daily feed intake (ADFI) was achieved by pigs consuming the 0.87% Lys diet (P < 0.05). Additionally, the lowest F:G was obtained by pigs fed the 0.79 and 0.87% Lys diet (P < 0.05). Based on broken-line and quadratic analysis models, the optimum Lys was 0.81 and 0.82% for ADG and F:G, respectively. In Exp. 3, 600 late finishing pigs (92.22 ± 2.41 kg bodyweight), were divided into 5 treatments providing Lys levels of 0.53, 0.60, 0.66, 0.73, and 0.79%. Each treatment had 5 replicates, 24 pigs per replication. Results showed that final bodyweight, ADG, ADFI, and F:G was not affected by increasing dietary Lys level, suggesting that the lowest SID Lys (0.53%) was sufficient for this group of pigs. Taken together, the SID Lys requirement for pigs from 30 to 60 kg, 60 to 90 kg, 90 to 120 kg was 0.94%, 0.81 to 0.82, and 0.53%, respectively, depending on the response criteria with performance maximized.

Association between serum arginine levels and cancer risk: A community-based nested case-control study

OBJECTIVE

The effect of arginine on tumors appears to be bidirectional. The association of serum arginine with the risk of incident cancer remains uncovered at present. We aimed to investigate the prospective relationship of baseline serum arginine concentrations with the risk of incident cancer in hypertensive participants.

MATERIALS AND METHODS

A nested, case-control study with 1,389 incident cancer cases and 1,389 matched controls was conducted using data from the China H-Type Hypertension Registry Study (CHHRS). Conditional logistic regression analyses were performed to evaluate the association between serum arginine and the risk of the overall, digestive system, non-digestive system, and site-specific cancer.

RESULTS

Compared with matched controls, cancer patients had higher levels of arginine (21.41 μg/mL vs. 20.88 μg/mL, p < 0.05). When serum arginine concentrations were assessed as quartiles, compared with participants in the lowest arginine quartile, participants in the highest arginine quartile had a 32% (OR = 1.32, 95% CI: 1.03 to 1.71), and 68% (OR = 1.68, 95% CI: 1.09 to 2.59) increased risk of overall and digestive system cancer, respectively, in the adjusted models. In the site-specific analysis, each standard deviation (SD) increment of serum arginine was independently and positively associated with the risk of colorectal cancer (OR = 1.35, 95% CI: 1.01 to 1.82) in the adjusted analysis.

CONCLUSION

We found that hypertensive individuals with higher serum arginine levels exhibited a higher risk of overall, digestive system, and colorectal cancer.

Effect of L-arginine and L-Lysine HCl ratio on growth performance and ileum morphology of native chickens aged 2-14 weeks

Background and Aim:

Micronutrients such as essential amino acids in chicken feed must be balanced to promote optimal development. The balance of the amino acids arginine and lysine in chicken feed is particularly important. This study aimed to examine the effect of the ratio of L-arginine to L-Lysine HCl on growth performance and ileum morphology of native chickens aged 2-14 weeks-old.

Materials and Methods:

One hundred and eighty 2-week-old native chickens which initial weight 78.10±4.97 g were classified into six treatments and five repetitions using a completely randomized design.

Treatments were based on the ratio of arginine to lysine in the feed:

T1 (0.50% L-arginine: 0.85% L-lysine HCl); T2 (0.75% L-arginine: 0.85% L-lysine HCl); T3 (1.00% L-arginine: 0.85% L-lysine HCl); T4 (0.50% L-arginine: 1.00% L-lysine HCl); T5 (0.75% L-arginine: 1.00% L-lysine HCl); and T6 (1.00% L-arginine: 1.00% L-lysine HCl).

Results:

Groups T3 and T6 had the highest feed consumption (42.06±0.29 and 42.78±0.72 g/bird/day, respectively), while Group T6 had the highest body weight and body weight gain rate (1505.60±103.20 kg/bird and 16.99±1.24 g/bird/day, respectively). Groups T3 and T6 also had the highest carcass weight (916.16±46.99 and 947.18±62.32 g/bird, respectively). The best feed conversion was seen for Groups T3, T5, and T6 (2.55±0.14, 2.50±0.20, and 2.53±0.19, respectively). For ileum morphometry, the highest villus height occurred in Groups T2, T3, T5, and T6 (962.80±23.31, 982.80±10.03, 972.80±18.99, and 989.80±10.69 μm, respectively); and Group T6 had the highest crypt depth and villus width (340.80±11.52 and 302.00±4.00 μm, respectively). Statistical analysis indicated significant differences among the treatment groups for all variables examined (p<0.05).

Conclusion:

The highest ratio of arginine-lysine was associated with the largest increase in native chicken feed consumption, body weight gain, feed conversion, and carcass weight, as well as villus height and width, and crypt depth in the ileum. Overall, an arginine-lysine ratio of 0.8-1.20 promoted optimal growth of native chickens aged 2-14 weeks. In the future, it is important to increase the arginine-lysine ratio with low feed protein levels in native chickens.

Growth promotion and antibiotic induced metabolic shifts in the chicken gut microbiome

Antimicrobial growth promoters (AGP) have played a decisive role in animal agriculture for over half a century. Despite mounting concerns about antimicrobial resistance and demand for antibiotic alternatives, a thorough understanding of how these compounds drive performance is missing. Here we investigate the functional footprint of microbial communities in the cecum of chickens fed four distinct AGP. We find relatively few taxa, metabolic or antimicrobial resistance genes similarly altered across treatments, with those changes often driven by the abundances of core microbiome members. Constraints-based modeling of 25 core bacterial genera associated increased performance with fewer metabolite demands for microbial growth, pointing to altered nitrogen utilization as a potential mechanism of narasin, the AGP with the largest performance increase in our study. Untargeted metabolomics of narasin treated birds aligned with model predictions, suggesting that the core cecum microbiome might be targeted for enhanced performance via its contribution to host-microbiota metabolic crosstalk.

This study compares the functional profiles of the cecal microbiome among chickens fed four different antimicrobial growth promoters. Chickens receiving narasin exhibited the largest performance increase via apparent nitrogen recycling by the core cecal microbiome.

Nitrogen and Boron Dosage Effects on Arginine Accumulation in Scots Pine Needles

Free arginine (Arg) content was observed to multiply when the level of nitrogen (N) nutrition was high, and additional fertilization with boron (B) potentiated this effect. Owing to this feature, conifers can be suggested for use as bioproducers of Arg. Concentrations of Arg in relation to N and B fertilization needed to be better understood. The effect of soil fertilization with N and B on accumulation of these elements and free Arg in one-year-old needles of 16-year-old Scots pine (Pinus sylvestris L.) trees was determined in this study. Plantations were fertilized with doses of N from 0 to 1000 kg ha−1 and B from 0 to 6 kg ha−1. Fertilization with 3 kg ha−1 B at N doses of 200–500 kg ha−1 stimulated the accumulation of N in needles of up to 3.1–3.6% dry weight (DW). The level of Arg in needles increased from 74.7 to 175.9 μmol g−1 DW at these levels of N and B.

Arginine metabolism and its functions in growth, nutrient utilization, and immunonutrition of fish

Fish have limited ability in endogenous biosynthesis of arginine. Arginine is an indispensable amino acid for fish, and the arginine requirement varies with fish species and fish size. Recent studies on fish have demonstrated that arginine influences nutrient metabolism, stimulates insulin release, is involved in nonspecific immune responses and antioxidant responses, and elevates disease resistance. Specifically, arginine can regulate energy homeostasis via modulating the adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) pathway, and also regulate protein synthesis via activating the target of rapamycin (TOR) signaling pathway. The present article reviews pertinent knowledge of arginine in fish, including dietary quantitative requirements, endogenous anabolism and catabolism, regulation of the endocrine and metabolic systems, and immune-regulatory functions under pathogenic challenge. Our findings showed that further data about the distribution of arginine after intake into specific cells, its sub-cellular sensor to initiate downstream signaling pathways, and its effects on fish mucosal immunity, especially the adaptive immune response against pathogenic infection in different species, are urgently needed.

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.

Aspects of transition cow metabolomics-Part I: Effects of a metaphylactic butaphosphan and cyanocobalamin treatment on the metabolome in liver, blood, and urine in cows with different liver metabotypes

Dairy cows in modern production systems are at risk to develop metabolic disorders during the transition period. Reasons for individual differences in susceptibility, as well as the underlying pathomechanisms, are still only partially understood. The development of metaphylactic treatment protocols is needed. In this context, an on-farm prospective 3-fold blinded randomized study involving 80 German Holstein cows was performed throughout 1 yr. The trial involved a thorough recording of the production and clinical traits, clinical chemistry, and liver biopsies and blood and urine sampling at d 14 (mean: 12 d, range: 1-26 d) antepartum (AP), and d 7 (7, 4-13) and 28 (28, 23-34) postpartum (PP) for metabolomics analyses. Two groups received a treatment with butaphosphan and cyanocobalamin (BCC) at either the dosage recommended by the manufacturer or the double dosage (5 or 10 mL/100 kg of body weight 10% butaphosphan and 0.005% cyanocobalamin (Catosal, Bayer Animal Health), n = 20 in each group, parity: 4.2 ± 2.0 and 3.4 ± 1.3, respectively (mean ± SD)] and one group a placebo treatment (NaCl 0.9%, n = 40, parity: 4.0 ± 1.9). The animals were treated at 6 time points (7, 6, and 5 d AP, and 1, 2, and 3 d PP) via intravenous injection. Mass spectroscopy-based targeted metabolomics analysis of blood plasma and liver samples were performed using the AbsoluteIDQ p180 kit (Biocrates Life Sciences), whereas the urine samples were analyzed by nuclear magnetic resonance spectroscopy. Statistical analysis was performed using multivariate [partial least squares discriminant analysis (PLS-DA)] and univariate methods (linear mixed model). Multivariate data analysis (PLS-DA plots) of the liver metabolome revealed 3 different metabotypes (A = medium, B = minor, C = large alterations in liver metabolome profile between AP and PP status). Metabotype B animals were characterized by higher PP lipomobilization (stronger PP body condition decrease and higher blood bilirubin, fatty acids, gamma-glutamyltransferase, and triglyceride levels) and a higher occurrence of transition cow diseases, compared with the animals in metabotype C. Analysis of the feeding data showed that the period of metabotype B animals (calving in a distinct time frame) was characterized by a decreased grass silage quality. The PP liver metabolome of the metabotype C animals was characterized by higher concentrations of AA, acylcarnitines, lysoPC and sphingomyelins compared with metabotype B. For the metaphylactic treatment with BCC a dose-dependent effect was confirmed, differing between the metabotypes. In all matrices and metabotypes at various time points significant treatment effects were observed, with different profiles in clinical chemistry and as well in metabolomics data. The most clear-cut treatment effect was observed in metabotype B in the liver at 7 d PP, characterized by an increase in several acylcarnitines and phosphatidylcholines, indicating a more efficient influx and oxidation of fatty acids in mitochondria and thereby an increase in energy supply and more efficient triglyceride export in the liver. The results from the liver metabolomics analysis support the application of an indication-based metaphylactic treatment with BCC.

Intestinal resection affects whole-body arginine synthesis in neonatal piglets

BACKGROUND

Previous studies in piglets show a direct relationship between intestinal mass and arginine (Arg) synthesis. We aimed to study the effects of 75% intestinal resection on whole-body Arg synthesis.

METHODS

Piglets were allocated to sham or jejunocolic (JC) surgery and to enteral nutrition (EN) at 20% [sham (n = 8), JC (n = 10)], or 40% [sham (n = 4), JC (n = 5)]. A gastric tube was placed for EN and a venous catheter for parenteral nutrition and blood sampling. On day 6, a primed bolus and constant infusion of Arg m + 2 label and proline m + 1 label was delivered. In addition, 40% EN piglets received a citrulline (Cit) m + 3 tracer. Blood sampling was undertaken and whole-body Arg synthesis was calculated. On day 7, intestinal length was measured, and samples were collected for gene expression (PCR quantification) and histopathology.

RESULTS

On Day 7, sham piglets showed intestinal lengthening compared to JC (p = 0.02). Whole-body Arg synthesis was similar between groups (p = 0.50). Adjusting for absolute small intestinal length, JC piglets had greater Arg synthesis (p = 0.01). Expression of arginosuccinase was upregulated in the jejunum of JC compared to sham on 20% EN (p = 0.03).

CONCLUSION

This demonstrates for the first-time adaptive changes in intestinal Arg synthesis following intestinal resection.

IMPACT

The intestine makes a critical contribution to whole-body arginine synthesis, particularly in neonates, a human population at risk for short bowel syndrome. Therefore, we studied intestinal arginine synthesis in a neonatal piglet model of short bowel syndrome and demonstrated adaptive changes in the intestine that may preserve whole-body arginine synthesis, despite loss of intestinal mass. This research adds new information to our understanding of the effects a massive intestinal resection has on amino acid metabolism during neonatal development.

Effects of Arginine Supplementation on Serum Metabolites and the Rumen Bacterial Community of Sika Deer (Cervus nippon)

Velvet antler is a regeneration organ of sika deer (Cervus nippon) and an important Chinese medicine, and nutrient metabolism affects its growth. Here, we investigated the effects of arginine supplementation on antler growth, serum biochemical indices, and the rumen bacterial community of sika deer during the antler growth period. Fifteen male sika deer (6 years old) were randomly assigned to three dietary groups, which were supplemented with 0 (n = 5, CON), 2.5 (n = 5, LArg), or 5.0 g/d (n = 5, HArg) L-arginine. The IGF-1, ALT and AST concentrations in the serum of LArg sika deer were significantly higher than those in the serum of CON (P < 0.05) and HArg deer (P < 0.05). The phyla Bacteroidetes, Firmicutes, and Proteobacteria were dominant in the rumen of sika deer among the three groups. Comparison of alpha diversities showed that the ACE and Chao1 indices significantly increased in the LArg and HArg groups compared with those in the CON group. PCoA and ANOSIM results showed that the bacterial community was significantly changed between the CON and LArg groups. Moreover, the relative abundances of Fibrobacter spp. and Prevotellaceae UCG-003 increased, but those of Clostridium sensu stricto 1 and Corynebacterium 1 decreased in the LArg and HArg groups compared with those in the CON group. Additionally, the relative abundances of 19 OTUs were significantly different between the LArg and HArg groups. These results revealed that arginine supplementation affected the sika deer rumen bacterial community and serum biochemical indices.

Response of meat chickens to different sources of arginine in low-protein diets

Arginine activity in broiler diets can be supplied by L-arginine (Arg), guanidinoacetic acid (GAA) and L-citrulline (Cit), all of which are commercially available. This study was conducted to assess the effects of Arg source and level on broiler performance, nutrient digestibility and carcass parameters. Day-old Ross 308 cockerels (n = 768) were assigned to one of eight dietary treatments using a completely randomized design: normal protein (NP), low protein deficient in Arg (LP) and LP with two levels of either Arg (0.238% and 0.476%), GAA (0.309% and 0.618%) or Cit (0.238 and 0.476%). The LP was 5 percentage points lower in protein level than the NP. Wheat, sorghum, soya bean meal, canola meal, and meat and bone meal-based diets were fed over three feeding phases to 6 replicate floor pens with 16 birds each. Compared to NP, birds fed LP had reduced feed intake (FI, p < 0.001), reduced body weight gain (BWG, p < 0.001) and increased feed conversion ratio (FCR, p < 0.001) from day 0 to day 35. Additions of Arg or Cit to the LP at both levels resulted in increased BWG and reduced FCR (p < 0.05). Birds fed LP with GAA added had lower FCR (p < 0.05) but not higher BWG (p > 0.05) compared with the LP observed from day 0 to day 35. Supplementation of Arg, Cit and the low level of GAA to LP resulted in increased carcass yield, bone length, diameter and ash (p < 0.05) but did not increase ileal energy or nitrogen digestibility (p > 0.05). The findings indicate that Cit is an efficacious source of Arg activity in Arg-deficient diets.

Amino acid profile of food fishes with potential to diversify fish farming activity

In Brazil, 47% of the fish farming correspond to the tilapia species, and the main producers are the south and northeast regions. This work aimed at characterizing the amino acid profile of three fishes with the potential for rearing and diversification in Brazil and worldwide. The fishes grass carp (Ctenopharyngodon idella), pacu (Piaractus mesopotamicus), and catfish (Ictalurus punctatus) were obtained from a rural property located in the city of Pato Branco, PR, Brazil, and analyzed regarding the amino acid composition through High-Performance Liquid Chromatography. The amino acid profile showed the presence of glutamic acid, followed by lysine, aspartic acid, and leucine as the most prominent amino acids for the three fishes. Among the studied species, the grass carp presented the highest content of essential amino acids, registering all values superior to the minimum recommendation standards determined by the Food and Agriculture Organization of the United Nations (FAO). The disclosure of the significant nutritional value presented by these species consolidate their protein quality and expand possibilities to improve the fish farming and development of derivative products.

Amino Acid Nutrition for Optimum Growth, Development, Reproduction, and Health of Zoo Animals

Proteins are large polymers of amino acids (AAs) linked via peptide bonds, and major components for the growth and development of tissues in zoo animals (including mammals, birds, and fish). The proteinogenic AAs are alanine, arginine, aspartate, asparagine, cysteine, glutamate, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine. Except for glycine, they are all present in the L-isoform. Some carnivores may also need taurine (a nonproteinogenic AA) in their diet. Adequate dietary intakes of AAs are necessary for the growth, development, reproduction, health and longevity of zoo animals. Extensive research has established dietary nutrient requirements for humans, domestic livestock and companion animals. However, this is not true for many exotic or endangered species found in zoos due to the obstacles that accompany working with these species. Information on diets and nutrient profiles of free-ranging animals is needed. Even with adequate dietary intake of crude protein, dietary AAs may still be unbalanced, which can lead to nutrition-related diseases and disorders commonly observed in captive zoo species, such as dilated cardiomyopathy, urolithiasis, gut dysbiosis, and hormonal imbalances. There are differences in AA metabolism among carnivores, herbivores and omnivores. It is imperative to consider these idiosyncrasies when formulating diets based on established nutritional requirements of domestic species. With optimal health, populations of zoo animals will have a vastly greater chance of thriving in captivity. For endangered species especially, maintaining stable captive populations is crucial for conservation. Thus, adequate provision of AAs in diets plays a crucial role in the management, sustainability and expansion of healthy zoo animals.

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

Simple Summary

Historically, studies with amino acids have focused on protein synthesis and accretion, especially with eggs and meat, whereas less importance has been given to their secondary functions on the metabolism. However, certain amino acids, such as arginine, methionine, and cysteine are precursors for other essential molecules in the immune defense, antioxidant system, cell signaling, and gene expression, and can act as regulators in the growth and development of the animals. Because poultry are subjected to stressful conditions throughout their lives, the use of these amino acids and their secondary functions could beneficiate their general health. This review describes the metabolism of arginine, methionine, and cysteine and how they modulate different tissues, especially during challenging conditions. Arginine supplementation has been shown to modulate musculoskeletal health development, reduce fat accretion, and improve the antioxidant system. Moreover, methionine and cysteine could improve the bone development and have a potential in mitigating the negative effects caused by heat stress. Understanding how these amino acids can ameliorate stressful conditions may provide novel insights about their use as nutritional strategies to modulate the health status of chickens.

Abstract

Amino acids such as arginine, methionine, and cysteine are the precursors of essential molecules that regulate growth and health, being classified as functional amino acids. This review describes the metabolism of arginine and the sulfur amino acids and how they modulate, directly or indirectly, different tissues. Emphasis is placed on their effects in supporting health during challenging conditions, such as heat stress and Eimeria infection. The use of arginine has been shown to reduce abdominal fat pad in ducks and increase lean tissue and bone mineral density in broilers. Additionally, the sulfur amino acids have been shown to improve bone development and are beneficial during heat stress. The use of L-methionine increased the cortical and trabecular bone mineral densities, in laying hens. Moreover, the dietary inclusion of these amino acids could reduce the damage caused by Eimeria spp. infection by regulating the antioxidant system and cell repair. Understanding how these amino acids can mitigate stressful conditions may provide us novel insights of their use as nutritional strategies to modulate the health status of chickens.

Dietary L-citrulline supplementation modulates nitric oxide synthesis and anti-oxidant status of laying hens during summer season

Background

L-citrulline (L-Cit), a non-protein amino acid, has been implicated in several physiological functions including anti-inflammatory, anti-oxidative, and hypothermic roles, however, there is a paucity of information with regards to its potential in poultry production.

Methods

This study was designed to investigate the effects of dietary L-Cit supplementation on the production performance, nitric oxide production, and antioxidant status of laying hens during summer period. Hy-Line Brown laying hens (n = 288, 34 weeks old) were allotted to four treatment, 6 replicates of 12 chickens each. Dietary treatments of control (basal diets), 0.25%, 0.50% and 1.00% L-Cit supplementation were fed to chickens for eight (8) weeks. Production performance, free amino acid profiles, nitric oxide production, and antioxidant properties were measured. Blood samples were collected at the 4^th and 8^th weeks of the experiment.

Results

Air temperature monitoring indicated an average daily minimum and maximum temperatures of 25.02 °C and 31.01 °C respectively. Dietary supplementation with L-Cit did not influence (P > 0.05) the production performance, and rectal temperature of laying hens. Egg shape index was increased (P < 0.05) with increasing levels of L-Cit. Serum-free content of arginine, citrulline, ornithine, tryptophan, histidine, GABA, and cystathionine were elevated, but taurine declined with L-Cit diets. Plasma nitric oxide (NO_x) concentration was highest at 1% L-Cit. Likewise, nitric oxide synthase (NOS) activity for total NOS (tNOS) and inducible NOS (iNOS) were upregulated with increasing L-Cit levels, although, tNOS was not affected at the 4^th week. Anti-oxidant enzymes including catalase and superoxide dismutase (SOD) were increased with L-Cit supplementation, however, SOD activity was unchanged at 4^th week, while total anti-oxidant capacity increased at the 8^th week. L-Cit supplementation attenuated the extent of lipid peroxidation, and also inhibited glutathione peroxidase activity.

Conclusion

Dietary L-Cit supplementation modulated systemic arginine metabolism, nitric oxide synthesis, antioxidant defense system, and increased the egg shape index of laying hens during the summer season. 1% L-Cit supplementation proved most effective in potentiating these effects and may be adopted for feed formulation strategies.

Impact of enteral arginine supplementation on lysine metabolism in humans: A proof-of-concept for lysine-related inborn errors of metabolism

Patients with lysine-related inborn errors of metabolism (pyridoxine-dependent epilepsy [PDE] and glutaric aciduria type 1 [GA1]), follow a lysine-restricted diet with arginine-fortified lysine-free amino acid formula and additional oral arginine supplementation as a newer therapy for PDE. The rationale of arginine supplementation is based on arginine's ability to compete with lysine transport across cell membranes via shared transporter systems. Adequate doses of arginine required to competitively inhibit enteral lysine uptake has not been studied in humans This proof-of-concept study investigates the effect of incremental enteral arginine doses on whole-body lysine oxidation using an in vivo stable isotope tracer, L-[1-¹³ C] lysine, in healthy humans. Five healthy men completed six study days each consuming one dose of l-arginine HCl per study day; range = 50-600 mg/kg/d. Lysine intake was at DRI (30 mg/kg/d). Breath samples were analysed for L-[1-¹³ C] lysine oxidation to ¹³ CO₂ using an isotope ratio mass spectrometer. Plasma amino acid concentrations were analysed using an amino acid analyser. Increasing doses of l-arginine HCl caused a linear decrease in whole-body lysine oxidation. Plasma arginine concentration increased, and plasma lysine concentration decreased below normal range with high arginine intakes. We provide the first empirical evidence of arginine-lysine antagonism in response to increasing oral arginine doses. Results suggest 300-600 mg/kg/d of l-arginine HCl and lysine intake restricted to DRI is needed to reduce enteral lysine uptake and systemic lysine oxidation. This could potentially lead to a recommended dose for arginine in lysine-related inborn errors of metabolism.

The effect of different dietary ratios of lysine, arginine and methionine on biochemical parameters and hormone secretion in turkeys

We postulated that the use of optimal levels and proportions of Lys, Arg and Met in compound feed allows for optimal exploitation of the growth potential of contemporary slaughter turkey hybrids and reduces metabolic disorders. The aim of the study was to determine the effect of different proportions of Lys, Arg and Met in diets whose Lys content is in accordance with NRC recommendations, that is a low level, on selected parameters of protein, lipid and carbohydrate metabolism and on hormone secretion in turkeys. The lowest Arg content (90% Lys) in the diet resulted in an increase in plasma total cholesterol levels in the turkeys as compared to higher Arg content (100% or 110% of Lys), (2.50 vs. 2.09 vs. 1.83). Plasma HDL and creatinine concentration increased in turkeys fed diets with higher Arg content (100% and 110% Lys) compared to turkeys receiving the diet with the lowest Arg content (90% Lys). Compared to turkeys receiving the lowest and intermediate Arg content (90% and 100% Lys), the diet with the highest content of this AA (110% Lys) resulted in an increase in the plasma T4 level (71.21 vs. 86.60 vs. 128.2). The varied Arg and Met levels relative to Lys did not affect the secretion of neurotransmitters or hormones regulating glucose metabolism. At low levels of Met in the diet, an decrease in Arg relative to Lys from 100% to 90% caused a growth depression of turkeys (10.68 vs. 10.21 kg), which was not noted in the case of the higher Met content. When using the Lys level recommended by NRC in the turkey diet, the optimal Arg level is 100% and Met is 45% compared to Lys.

The Role of Arginine in Disease Prevention, Gut Microbiota Modulation, Growth Performance and the Immune System of Broiler Chicken – A Review

The effect of dietary arginine on disease prevention, immune system modulation, the gut micro-biota composition and growth of broiler chicken was reviewed. The main aim of poultry production is the maximization of profit at the least possible cost. This objective can mainly be achieved by ensuring that there is no interference in growth or disease outbreak and by feeding chicken with the best possible level of nutrients. With the ban on antibiotic growth promoters, attention is shifted towards other nutrition methods to prevent diseases and promote growth. More attention is therefore given to protein diets in animal nutrition due to their importance as essential part of active biological compounds in the body, assisting in the breakdown of body tissue and helping in the physiological processes of the animal. Arginine plays important function in serving as building blocks of proteins and polypeptides. It performs other roles during the regulation of important biochemical functions such as maintenance, growth, reproduction and immunity. Arginine cannot be synthesized by the body so it has to be supplemented in the diet. When arginine is supplemented above the recommended level, the gut mucosa is protected, immunosuppression is alleviated, diseases like necrotic enteritis, infectious bursal disease and coccidiosis in broiler chickens are prevented. There is an improvement in growth resulting from the increase in intestinal absorption, barrier function and microbiota composition.

Evolutionary expression differences of creatine synthesis-related genes: Implications for skeletal muscle metabolism in fish

The creatine/phosphocreatine system is the principal energy buffer in mammals, but is scarcely documented in fish. We measured the gene expression of major enzymes of this system, glycine amidinotransferase (GATM), guanidinoacetate N-methyltransferase (GAMT) and muscle-type creatine kinase (CKM) in kidney, liver, and muscle tissues of fish and mammals. CKM was expressed strongly in the muscles of all examined species. In contrast, GATM and GAMT were strongly expressed in the muscle tissue of fish, but not of mammals. This indicates that creatine synthesis and usage are spatially separated in mammals, but not in fish, which is supported by RNA-Seq data of 25 species. Differences in amino acid metabolism along with methionine adenosyltransferase gene expression in muscle from fishes but not mammals further support a central metabolic role of muscle in fish, and hence different organization of the creatine/phosphocreatine biosynthesis system in higher and lower vertebrates.

Nutritional implications of feeding reduced-protein diets to meat chickens

Global interest has emerged for the implementation of reduced-protein diets for meat chickens. The necessity of their development stems from environmental impacts and health and welfare concerns surrounding current meat-chicken production. Reduced crude-protein diets are possible with the increasing affordability of supplemental crystalline amino acids. Supplementing broiler feed with methionine, lysine and threonine is common practice in industry and has enabled a reduction of dietary crude protein to the levels currently used. However, further reduction of dietary protein often results in poor performance. Several nutritional options have been investigated with a focus on crystalline essential and non-essential amino acids such as glycine. However, reducing the crude protein of meat-chicken diets does change the ingredient and nutrient profile aside from the amino acid composition. Alterations in non-protein nitrogen concentrations, dietary electrolyte balance, minerals, fibre and carbohydrates, methyl-donors and polyphenols must be considered in formulations to ensure successful implementation of reduced-protein diets. The ability to maintain performance with reduced-protein diets may benefit sustainability and longevity of the meat-chicken industry.

In ovo feeding of l-arginine regulates intestinal barrier functions of posthatch broilers by activating the mTOR signaling pathway

BACKGROUND

During the last phase of incubation, dramatic physiological and metabolic changes occur in chick embryos, and supplies of nutrients and energy are always insufficient. This study investigated the effects of in ovo feeding (IOF) of l-arginine (Arg) on the hatchability, growth performance, intestinal development and functions of posthatch broilers.

RESULTS

The IOF of Arg increased (P < 0.05) the feed intake and body weight gain during 1-21 days and 1-42 days, and the intestinal weight of 7- and 21-day-old broilers, compared with non-injected control and diluent-injected groups. The IOF of Arg increased (P < 0.05) villus height (VH), ratio of VH to crypt depth (CD) and density of goblet cells, and decreased (P < 0.05) the CD in jejunum of 1-, 7- and 21-day-old broilers. The IOF of Arg also increased (P < 0.05) the percentage of proliferating cell nuclear antigen positive cells of villus, and the mRNA expressions of mucin-2, claudin-1, zonula occludens-1 and -2 in jejunal mucosa of 21-day-old broilers. Meanwhile, IOF of Arg increased (P < 0.05) the protein abundance of phosphorylated mechanistic target of rapamycin (mTOR), ribosomal protein S6 kinase 1 and eukaryotic initiation factor 4E binding protein 1 in jejunal mucosa.

CONCLUSION

The IOF of Arg improved the development and barrier functions of small intestine, which might be associated with activating the mTOR pathway. In addition, the improved intestinal development might explain the improvement in feed intake and consequently the growth performance of broilers. Therefore, IOF of Arg solution could be an effective technology for regulating early nutrition supply and subsequent growth development in the poultry industry. © 2017 Society of Chemical Industry.

Effect of in ovo feeding of l-arginine on the hatchability, growth performance, gastrointestinal hormones, and jejunal digestive and absorptive capacity of posthatch broilers

This study was conducted to investigate the effects of in ovo feeding (IOF) of Arg solution on the hatchability, growth performance, gastrointestinal hormones, serum AA, activities of digestive enzymes, and mRNA expressions of sensing receptors and nutrient transporters in the jejunum of posthatch broilers. One thousand two hundred embryonated eggs with similar weight were randomly allocated to 5 groups consisting of 8 replicates of 40 eggs each. The 5 treatments were arranged as a noninjected control, a diluent-injected (0.75% NaCl solution) group, and Arg solution-injected groups with 0.5%, 1.0%, and 2.0% Arg, all dissolved in diluent. At 17.5 d of incubation, 0.6 mL of IOF solution was injected into the amniotic fluid of each egg of the injected groups. Results showed the hatchability of the 2% Arg group was lower (linear, = 0.025) than that of the other groups, and the BW of 21-d-old broilers increased (linear, = 0.008; quadratic, = 0.003) with increasing IOF concentration of Arg. The ADFI (linear, = 0.005; quadratic, = 0.001) and ADG (linear, = 0.010; quadratic, = 0.004) increased during d 1 to 21 with increasing IOF concentration of Arg. For 7- and 21-d-old broilers, the weights of digestive organs increased (linear, < 0.05) with increasing IOF concentrations of Arg; the greatest values were observed in the 1% Arg group. For 21-d-old broilers, IOF of the 1% Arg solution increased ( < 0.05) the concentrations of ghrelin and glucagon-like peptide 2; the activities of digestive enzymes, alkaline phosphatase, maltase, and sucrase in the jejunum; and the concentrations of serum AA of Val, Met, Ile, Leu, Arg, and Pro compared with those of the noninjected control and diluent-injected group. In ovo feeding of the 1% Arg solution also increased ( < 0.05) the mRNA expressions of jejunal sensing receptors of taste receptor type 1 members 1 and 3; the G protein-coupled receptor, class C, group 6, subtype A; nutrient transporters of solute carrier family 7, members 4, 6, and 7; sodium-glucose transporter 1; and fatty acid-binding protein 1. In conclusion, the 1% Arg solution was the appropriate injection level. In ovo feeding of the 1% Arg solution did not affect the hatchability but facilitated the release of gastrointestinal hormones, increasing the digestive and absorptive capacity and finally improving the growth performance of 21-d-old broilers. Therefore, IOF of the appropriate Arg solution could be an effective technology for regulating early nutrition supply and subsequent growth development in the poultry industry.

Interactive effects of dietary arginine and Eimeria acervulina infection on broiler growth performance and metabolism

The influence of dietary Arg concentration and Eimeria acervulina infection on broiler growth performance and plasma carotenoid, nitric oxide (NO), amino acid, and urea concentrations was evaluated. Male Ross × Ross 308 broilers (384 total) were fed a common diet for 10 d post-hatch and provided experimental diets formulated to contain 1.23 (HA) or 0.74% (LA) standardized ileal digestible Arg from 10 to 28 d. At 21 d, one-half of the broilers were switched to the opposite diet to create 4 dietary regimens where birds were fed the LA diet throughout, the LA diet replaced by the HA diet at 21 d, the HA diet throughout, or the HA diet replaced by the LA diet at 21 d. Broilers were orally inoculated 0 (uninfected) or 3.5 × 105 sporulated E. acervulina oocysts at 15 d, resulting in a factorial arrangement of 4 dietary regimens × 2 infection states (8 replicates/treatment). Overall (10 to 28 d) BW gain and G:F were greatest (P < 0.01) for birds fed the HA diet throughout, regardless of infection status. Eimeria acervulina infection decreased (P < 0.01) BW gain of birds from 15 to 21 d, and G:F was lowest (P < 0.05) for infected birds fed the LA diet during this period. There was no influence (P > 0.05) of E. acervulina on BW gain or G:F of broilers from 21 to 28 d. Plasma Arg, Lys, and Orn levels at 21 d indicated that the LA diet caused an imbalance in the Lys and Arg status of broilers, and E. acervulina infection increased (P < 0.01) the plasma concentration of these 3 amino acids. Diet × infection interactions (P < 0.05) were observed on 21 d for plasma carotenoids and NO, whereby infection decreased plasma carotenoids and increased plasma NO, but dietary Arg concentration only influenced these measures for uninfected birds. Thus, production of NO during E. acervulina infection was not impaired by dietary Arg limitation.

Evaluation of three popular diets fed to pet sugar gliders (Petaurus breviceps): Intake, digestion and nutrient balance

Three diets fed to 12 pair-housed sugar gliders, Petaurus breviceps, were evaluated through 5-day intake and digestion trials following 10-day transitions. Diets 1 and 2 comprised liquid formula mixes with added vegetables and fruit, and Diet 3 comprised extruded pellets and a liquid formula. Diets eaten contained 16 -19% crude protein, 3%-15% crude fat, 10%-11% neutral detergent fibre, 4%-20% starch and 8%-49% sugar (dry basis). Calculated individual dry matter intakes (DMI) ranged from 3.9 to 5.1 g/day, representing 58.2-78.4 kJ/day. DMI was greater for Diet 2 (7.2% BW) vs. Diet 1 (5.6; p = .006) and Diet 3 (4.2% BW; p = .003). Although these differences were no longer detectable on a MBW basis, animals were shown to have gained BW (+14.2 g; p = .03) on Diet 2. In addition to nutrient composition differing widely among diets, DM digestibility (DMD) was higher in Diet 1 (91.2%) compared to Diet 2 (87.3%; p = .03), but DMD for Diet 3 (88.9%) did not differ from other diets. Gliders demonstrated ability to digest a variety of energy substrates, including simple sugars (96%-99%), fats (81%-96%) and starches (79%-98%), as well as substantial insoluble dietary fibre (58%-75%), with significant difference among diets demonstrated for some nutrients. Animals displayed selective feeding behaviours, rejecting insoluble fibre in produce and preferring the lipid-coated exterior of pellets. The diets used appeared to be balanced with respect to energy, protein and macromineral content, but may predispose to iron excess, other mineral imbalances (especially Ca deficiency) and obesity-clinical health issues described for pet gliders. Future focus on concentrations, types and utilization of dietary fibre in natural and captive diets, vitamin D metabolism and trace mineral interactions in sugar gliders would assist diet optimization for this highly gummivorous species.

Comparative effect of arginine and/or tryptophan in ovo feeding on hatchability percentage, growth performance and economic importance of commercial broiler

In ovo feeding is the administration of exogenous nutrients into the amnion of the late-term avian embryo so that the avian embryo orally consumes the amniotic fluid (primarily water and albumen protein) prior to pipping the air cell. So the study was carried out to find out the effect of in ovo nutrition on post-hatch performances in broilers. Total 700 fertile eggs of Cobb 400 with uniform egg weight were divided into 5 groups: non-injected control, injected control (0.5 ml of 0.9% normal saline), arginine (0.5 ml of 0.5% arginine), tryptophan (0.5 ml of 0.5% tryptophan) and combination (0.25 ml of 0.5% each of arginine and tryptophan); and injected on 18 d of incubation into amnion. On the 21d, 108 chicks were randomly selected from each treatment in total accounting 540 chicks. The hatchability and hatch weight were studied where arginine had shown a highly significant improved hatch weight and placement weight. There was no significant difference in feed efficiency, but cumulative feed intake was higher in tryptophan and combination groups. Body weight and body weight gain had also resulted significantly in arginine fed in ovo groups up to 21d of age. The broiler farm economy index (BFEI) and broiler feed price ratio (BFPR) were best in tryptophan and arginine in ovo fed groups, respectively.