Role of Dietary L-Arginine in Poultry Production

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.

Research note: Effects of L-carnitine and L-arginine on sperm quality and fertility potential of aged broiler breeder roosters

This objective of this study was to investigate the effects of L-arginine (L-Arg) and L-carnitine (LC) and their mixture in the diet (at lower levels) on sperm quality in aging broiler breeder roosters. Thirty-two broiler breeder roosters of the Arian breed were kept at 50 wk of age after a 12-wk acclimatization period. The birds were divided into four treatments and eight replicates in a completely randomized design. Treatments included (1) control (CON), 2) diet supplemented with 150 mg LC per kg diet, (3) diet supplemented with 500 mg L-Arg per kg diet, and (4) diet supplemented with 75 mg LC + 250 mg L-Arg. The use of LC in the roosters' diet increased the concentration, percentages of total mobility, progressive motility, curvilinear velocity and straight line velocity compared to the CON and L-Arg treatment (P < 0.05). The percentage of apoptosis was lower in the LC, L-Arg + LC and L-Arg groups than in the CON group (P < 0.05). In general, LC and the mixture of LC and L-Arg probably improve the sperm quality of aged cockerels through the supply of adenosine triphosphate, antioxidant effects, and the synthesis of nitric oxide.

Dietary supplementation with 15% tomato pomace (Solanum lycopersicum L.) improves sperm production and antioxidant status in aged male broiler breeders

The objective was to investigate effects of dietary tomato pomace (TP) and L-Arginine (L-Arg; 10% above nutritional recommendation) in aged male broiler breeders. Thirty male broiler breeders (Ross 308), 58 wk old, were randomly and equally allocated into five experimental groups: basal diet (C); 5% TP-supplemented (T-5); 10% TP-supplemented (T-10); 15% TP-supplemented (T-15); and L-Arg supplemented (L-10) groups. In contrast to the Control and TP-supplemented groups, sperm of L-10 roosters had higher C14:1, C16:0 and C18:1 n-9c proportions, total saturated fatty acid (FA) contents, and n-6:n-3 ratios, but a lower C22:4 n-6 content (P<0.05). However, sperm of T-15 roosters had increased C18:2 n-6, C22:6 n-3 and total unsaturated FA contents but reduced n-6:n-3 ratios compared to Control birds (P<0.05). Additionally, serum of T-15 roosters had lower cholesterol and triglyceride (TG) concentrations, along with decreased aspartate aminotransferase (AST) activity (P<0.05). In serum of T-15 and L-10 roosters, there were increases (P<0.05) in total antioxidant capacity (TAC) and uric acid (UA) and a reduction (P<0.05) in malondialdehyde (MDA) concentration. The T-15 roosters had higher (P<0.05) serum testosterone concentration and testes glutathione peroxidase (GPx) activity. Superoxide dismutase (SOD) content was reduced (P<0.05) in L-10 roosters. Seminiferous tubule diameter (STD) and seminiferous epithelium thickness (SET) were increased in all groups fed TP (P<0.05) and T-10 and T-15 roosters had increases (P<0.05) in tubular differentiation indices (TDI). The T-15 and L-10 groups had higher mRNA expressions of AKT1 and Nrf2 (P<0.05). In conclusion, in aged male broiler breeders, up to 15% TP supplementation is recommended to improve reproductive performance by enhancing testes histology and antioxidant status.

Partial substitution of soybean meal with microalgae meal (Arthrospira spp. - Spirulina) in grower and finisher diets for broiler chickens: implications on performance parameters, footpad dermatitis occurrence, breast meat quality traits, amino acid digestibility and plasma metabolomics profile

This trial was conducted to evaluate the effects of replacing soybean meal with microalgae meal (MM; Arthrospira spp.) during grower and finisher phases on productive performance, footpad dermatitis (FPD) occurrence, breast meat quality, amino acid digestibility and plasma metabolomics profile of broiler chickens. One thousand day-old Ross 308 male chicks were divided into 5 experimental groups (8 replicates, 25 birds/each): CON, fed a commercial soybean-based diet throughout the trial (0-41 d); F3 and F6, fed the CON diet up to 28 d of age and then a finisher diet (29-41 d) with either 30 or 60 g MM/kg, respectively; and GF3 and GF6, receiving CON diet until 14 d and then diets containing 30 or 60 g MM/kg from 15 to 41 d, respectively. All diets were iso-energetic and with a similar amino acid profile. Growth performances were recorded on a pen basis at the end of each feeding phase and apparent ileal amino acid digestibility was determined at 41 d. Footpad dermatitis occurrence was assessed on all processed birds, while breast and plasma samples were collected for meat quality and metabolomics analysis (proton nuclear magnetic resonance - 1H-NMR). At 41 d, CON group showed higher body weight than F6 and GF6 ones (2,541 vs. 2,412 vs. 2,384 g, respectively; P < 0.05). Overall, GF6 group exhibited the highest feed conversion ratio, while F3 did not present significant differences compared to CON (1.785 vs. 1.810 vs. 1.934 g feed/g gain, respectively for CON, F3 and GF6; P < 0.01). The occurrence and the risk of developing FPD were similar among groups. MM administration increased breast meat yellowness and reduced amino acid digestibility (P < 0.001). The 1H-NMR analysis revealed variations in the levels of some circulating metabolites, including histidine, arginine and creatine, which play important metabolic roles. Overall, these findings can contribute to expand the knowledge about the use of Arthrospira spp. as protein source in broiler diets.

Muscle growth affects the metabolome of the pectoralis major muscle in red-winged tinamou (Rhynchotus rufescens)

The aim of the present study was to identify and quantify the metabolites (metabolome analysis) of the pectoralis major muscle in male red-winged tinamou (Rhynchotus rufescens) selected for growth traits. A selection index was developed for females [body weight (BW), chest circumference (CC), and thigh circumference (TC)] and males [BW, CC, TC, semen volume, and sperm concentration] in order to divide the animals into 2 experimental groups: selection group with a higher index (TinamouS) and commercial group with a lower index (TinamouC). Twenty male offspring of the 2 groups (TinamouS, n = 10; TinamouC, n = 10) were confined for 350 d. The birds were slaughtered and pectoralis major muscle samples were collected, subjected to polar and apolar metabolites extractions and analyzed by proton nuclear magnetic resonance (1H NMR) spectroscopy. Analysis of the polar metabolomic profile identified 65 metabolites; 29 of them were differentially expressed between the experimental groups (P < 0.05). The TinamouS groups exhibited significantly higher concentrations (P < 0.05) of 25 metabolites, including anserine, aspartate, betaine, carnosine, creatine, glutamate, threonine, 3-methylhistidine, NAD+, pyruvate, and taurine. Significantly higher concentrations of cysteine, beta-alanine, lactose, and choline were observed in the TinamouC group (P < 0.05). The metabolites identified in the muscle provided information about the main metabolic pathways (higher impact value and P < 0.05), for example, phenylalanine, tyrosine and tryptophan biosynthesis; alanine, aspartate and glutamate metabolism; D-glutamine and D-glutamate metabolism; β-alanine metabolism; glycine, serine and threonine metabolism; taurine and hypotaurine metabolism; histidine metabolism; phenylalanine metabolism. The NMR spectra of apolar fraction showed 8 classes of chemical compounds. The metabolome analysis shows that the selection index resulted in the upregulation of polyunsaturated fatty acids, unsaturated fatty acids, phosphocholines, phosphoethanolamines, triacylglycerols, and glycerophospholipids. The present study suggests that, despite few generations, the selection based on muscle growth traits promoted changes in metabolite concentrations in red-winged tinamou.

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 inositol-stabilized arginine silicate numerically reduced woody breast severity in male Ross 708 broilers without altering growth

The woody breast (WB) myopathy is an unintended outcome of fast broiler chicken growth and high breast muscle yields. Myodegeneration and fibrosis in the living tissue are results of hypoxia and oxidative stress driven by lack of blood supply to muscle fibers. The study aim was to titrate a vasodilator ingredient, inositol-stabilized arginine silicate (ASI), as a feed additive to improve blood flow and ultimately, breast meat quality. A total of 1,260 male Ross 708 broilers were assigned to: 1) a control basal diet, or the control diet plus increasing ASI: 2) 0.025% ASI, 3) 0.05% ASI, 4) 0.10% ASI, or 5) 0.15% ASI. At d 14, 28, 42, and 49, growth performance was measured on all broilers and serum from 12 broilers/diet was analyzed for creatine kinase and myoglobin presence. On d 42 and 49, 12 broilers/diet were measured for breast width, then left breast fillets were excised, weighed, palpated for WB severity, and visually scored for degree of white striping (WS). At 1 d postmortem, 12 raw fillets/treatment underwent compression force analysis, and at 2d postmortem, the same fillets were analyzed for water-holding capacity. mRNA was isolated from 6 right breasts/diet at both d 42 and 49 for qPCR quantification of myogenic gene expression. Birds fed the lowest dose of 0.025% ASI had a 5-point/3.25% feed conversion ratio reduction compared to birds fed 0.10% ASI over wk 4 to 6 and reduced serum myoglobin at 6-wk of age compared to the control. Breasts from birds fed 0.025% ASI received 42% greater normal WB scores at d 42 compared to control fillets. At d 49, breasts from broilers fed 0.10 and 0.15% ASI received 33% normal WB scores. At d 49, 0.025% AS-fed broiler breasts showed no severe WS. Increased myogenin expression was observed in 0.05 and 0.10% ASI breast samples on d 42 and myoblast determination protein-1 expression was upregulated in breasts from birds fed 0.10% ASI on d 49 compared to the control. Therefore, a dietary inclusion of 0.025, 0.10, or 0.15% ASI was beneficial in reducing WB and WS severity and promoting muscle growth factor gene expression at age of harvest without diminishing bird growth or breast muscle yields.

Assessment of Neurodegenerative Changes in Turkeys Fed Diets with Different Proportions of Arginine and Methionine Relative to Lysine

Simple Summary

It is important to take care of a properly balanced amino acid composition in the diet in order to inhibit or delay the occurrence of processes and changes related to the destruction of nervous tissue. Therefore, an attempt was made in this manuscript to evaluate the effect of different ratios of the key amino acids arginine and methionine, relative to lysine, in relation to two turkey feeding standards. The amino acid guidelines formulated by British United Turkeys (BUT) suggest higher levels of lysine (Lys) in turkey diets than those recommended by the National Research Council (NRC). In order to assess the impact of such supplementation, we analyzed the level of indicators informing the presence or degree of advancement of neurodegenerative processes in the nervous tissue (the level of acetylcholinesterase and amyloid-β; the concentration of AChE complexes with amyloid-β and Tau protein, called glycosylated acetylcholinesterase (GAChE), indicative of the destruction of neurons). The level of low-density lipoprotein receptor-related protein 1, or LRP-1, which facilitates the breakdown of toxic amyloid-β, was also assessed. In addition, the effect of different doses of these amino acids on neurodegenerative changes in DNA, especially the degree of methylation of histone proteins resulting from covalent modifications was compared between lysine and arginine residues.

Abstract

We postulated that the use of optimal levels and proportions of Arg and Met relative to a low or high concentration of Lys in diets for meat turkeys would reduce the occurrence of metabolic disturbances in the nervous tissue that can lead to neurodegenerative changes. The aim of the study was to determine the effect of various proportions of Lys, Arg, and Met in diets for turkeys, with a low content of Lys in accordance with NRC (Experiment 1) recommendations, and in diets with high Lys levels that are close to the recommendations of breeding companies (Experiment 2) on selected indicators of potential neurodegenerative effects in the brain and liver of turkeys. The Experiment 1 and Experiment 2 was conducted using 864 day-old turkey chicks randomly assigned to six groups, in eight replicates (6 groups × 18 birds × 8 replicates). A full description of the methodology can be found in previously published papers using the same experimental design. Indicators informing about the presence or advancement of neurodegenerative processes in the nervous tissue were determined in the brain and liver (level of: AChE, amyloid-β, GAChE, Tau protein, LRP1, and the degree of DNA methylation). It was established that in the case of both a low (National Research Council, NRC) and a high (British United Turkeys, BUT) level of Lys in the diet of turkeys, the Arg level can be reduced to 90% of the Lys level and Met to 30% of the Lys level, because this does not cause neurodegenerative changes in turkeys. Unfavorable neurodegenerative changes may appear if the Arg level is increased from 100 to 110% of the Lys level recommended by the NRC. However, due to the lack of such a relationship when Arg is increased from 100 to 110% of the Lys level recommended by BUT, at this stage of research no definitive conclusions can be drawn regarding the risk of neurodegenerative changes caused by increasing Arg in the diet of turkeys.

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.

Selected metabolic, epigenetic, nitration and redox parameters in turkeys fed diets with different levels of arginine and methionine

The amino acid guidelines formulated by British United Turkeys postulate higher levels of lysine (Lys) in turkey diets than those recommended by the National Research Council. However, any modifications in the Lys content of turkey diets should be accompanied by changes in the inclusion rates of other amino acids, including methionine (Met) and arginine (Arg). The research hypothesis postulates that the appropriate inclusion levels and ratios of arginine and methionine in turkey diets with high lysine content can improve the antioxidant status of turkeys without compromising their metabolism. The aim of this study was to determine the influence of different Arg and Met ratios in Lys-rich diets on biochemical indicators, redox status and epigenetic changes in turkeys. The turkeys were assigned to six groups with eight replicates per group and 18 birds per replicate. Six feeding programs, with three dietary Arg levels (90%, 100% and 110%) and two dietary Met levels (30% and 45%) relative to dietary Lys content were compared. During each of the four feeding phases, birds were fed ad libitum isocaloric diets with high Lys content. Our results show, that in growing turkeys fed diets with high Lys content, the inclusion rate of Arg can be set at 90% of Lys content with no negative effects on their antioxidant status, metabolism or performance. Diets with high Arg content (110% Lys) are not recommended due to the risk of lipid and protein damage, and an undesirable increase in insulin and T4 levels. Regardless of dietary Arg levels, an increase in the Met inclusion rate from 30% to 45% of Lys content minimizes the oxidation of lipids, proteins and DNA, and increases the antioxidant defense potential of turkeys.

L-Citrulline Influences the Body Temperature, Heat Shock Response and Nitric Oxide Regeneration of Broilers Under Thermoneutral and Heat Stress Condition

Heat stress (HS) adversely affects several physiological responses in organisms, but the underlying molecular mechanisms involved are yet to be fully understood. L-Citrulline (L-Cit) is a nutraceutical amino acid that is gaining research interest for its role in body temperature regulation and nitric oxide synthesis. This study investigated whether dietary supplementation with L-Cit (1% of basal diet) could ameliorate the effects of acute HS on thermotolerance, redox balance, and inflammatory responses of broilers. Ross 308 broilers (288 chicks) were subjected to two environments; thermoneutral at 24°C (TNZ) or HS at 35°C for 5 h, and fed two diets; control or L-Cit. The results showed that HS increased the ear, rectal (RT), and core body (CBT) temperatures of broilers, along with higher respiratory rate. The RT and CBT readings were intermittently affected with time effect, whereas, L-Cit supplementation lowered the mean CBT than the control diet. Antioxidant assays showed that superoxide dismutase was increased during HS, while, catalase was promoted by L-Cit supplementation. In addition, L-Cit induced glutathione peroxidase activity compared to the control diet during HS. Hypothalamic heat shock protein (HSP)-90 was upregulated by HS, but L-Cit downregulated heat shock factor (HSF)-1, and HSP 60 mRNA expressions. HSF 3 mRNA expression was downregulated by L-Cit under TNZ condition. More so, HS increased the plasma nitric oxide (NO) concentration but lowered the total NO synthase (tNOS) activity. In contrast, L-Cit supplementation limited NO production but increased the tNOS activity. Arginase activity was increased in the control fed group during HS but L-Cit supplementation lowered this effect. The NOS-COX pathway was significantly affected under TNZ condition, since L-Cit supplementation downregulated the mRNA expression of iNOS-COX2 in the hypothalamus, and further reduced the serum PGE2 concentration. Together, these data indicates that L-Cit influenced the antioxidant defense, heat shock response and nitric oxide regeneration both under thermoneutral and HS conditions; and that L-Cit may be directly and/or indirectly involved in the central regulation of body temperature.

The effect of different dietary ratios of lysine, arginine and methionine on protein nitration and oxidation reactions in turkey tissues and DNA

An assumption was made in the study that the optimal inclusion levels and ratios of lysine (Lys), arginine (Arg) and methionine (Met) in diets with Lys content consistent with National Research Council (NRC) recommendations (1994) contribute to stimulate the antioxidant defense system and prevent disorders resulting from the oxidation and nitration of biologically important molecules. The experiment was carried out on 864 one-day-old Hybrid Converter turkeys divided into six experimental groups (8 replicates per group and 18 birds per replicate) receiving different levels of Arg and Met. Chickens from group Arg₉₀Met₃₀ received 90% Arg and 30% Met relative to Lys; Arg₉₀Met₄₅ - 90% Arg and 45% Met relative to Lys; Arg₁₀₀Met₃₀ - 100% Arg and 30% Met relative to Lys; Arg₁₀₀Met₄₅ - 100% Arg and 45% Met relative to Lys; Arg₁₁₀Met₃₀ - 110% Arg and 30% Met relative to Lys and Arg₁₁₀Met₄₅ - 110% Arg level and 45% Met level relative to the content of dietary Lys. In comparison with turkeys fed diets with moderate Arg content (100% of Lys content), a decrease in dietary Arg level (90% of Lys content) led to a decrease in plasma 3-nitrotyrosine (3-NT) concentration (163.6 vs. 141.0), whereas an increase in dietary Arg level (110% of Lys content) led to an increase in plasma 3-NT concentration (163.6 vs. 202.6). In comparison with turkeys fed diets with moderate Arg content (100% of Lys content), the lowest dietary Arg level (90% of Lys content) decreased superoxide dismutase (SOD) activity in the intestinal wall (19.68 vs. 17.41) and in the liver (11.51 vs. 7.94), increased SOD activity in the blood (507.6 vs. 961.4) and in breast muscles (6.26 vs. 7.43) and increased the concentration of malondiadehyde in breast muscles (1.10 vs. 1.50). An increase in dietary Met content from 30 to 45% of Lys content caused a decrease in plasma protein carbonyl concentration (4.33 vs. 3.8) and catalase activity in breast muscles (54.70 vs. 49.66), and an increase in SOD activity in the liver (8.90 vs. 10.41). The highest dietary Arg level (110% of Lys content) did not induce the oxidation of lipids, proteins or DNA, but it increased the risk of protein nitration. The lowest dietary Arg level (90% of Lys content) deteriorated the antioxidant status of turkeys. Regardless of dietary Arg levels, an increase in Met content from 30 to 45% of Lys content stimulated the antioxidant defense system of turkeys.

Hepatic lipidosis in fattening turkeys: A review

The conditions on turkey fattening farms, including management, housing, and feeding, have been constantly improved recently in favour of animal health. Many studies deal scientifically with poultry health. However, specifically concerning liver health, there are still open questions regarding the influence of dietary factors on the metabolism and function of the liver. Consideration of the factors that could influence and alter liver metabolism is therefore of critical relevance. The liver, as a major metabolic organ, is the main site of fat synthesis in turkeys. Under certain conditions, fat can excessively accumulate in the liver and adversely affect the birds’ health. The so-called hepatic lipidosis (HL) in fattening turkeys has been known for years. This disease has unacceptable economic and animal welfare impacts, with high animal losses up to 15% within only a few days. To date, little is known about the causes and the metabolic changes in fattening turkeys leading to HL despite the increasing focus on health management and animal welfare. To understand what is different in turkeys compared to other species, it is necessary to discuss the metabolism of the liver in more detail, including HL-associated gross and microscopic lesions. In the current review, aspects of liver structure and lipid metabolism with special regard to lipogenesis are explained to discuss all dietary factors attributing to the development and prevention of HL. As part of the prevention of the HL, dietetics measures can be helpful in the future.

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.

Nutritional modulation of fertility in male poultry

The increased consumption of protein derived from poultry demands greater poultry production, but increased poultry production (meat and eggs) is dependent on the fertility of the parent flocks. Clearly, the fertility of poultry flocks is associated with the fertility of both males and females, but the low numbers of males used for natural or artificial insemination mean that their role is more important. Thus, enhancing the semen volume, sperm concentration, viability, forward motility, and polyunsaturated fatty acids in sperm, as well as protecting against oxidative damage, could help to optimize the sperm membrane functionality, mitochondrial activity, and sperm-egg penetration, and thus fertility. Therefore, this review summarizes the nutritional factors that could improve the fertility of poultry males as well as their associated mechanisms to allow poultry producers to overcome low-fertility problems, especially in aging poultry males, thereby obtaining beneficial impacts on the poultry production industry.

The effect of different dietary ratios of lysine and arginine in diets with high or low methionine levels on oxidative and epigenetic DNA damage, the gene expression of tight junction proteins and selected metabolic parameters in Clostridium perfringens-challenged turkeys

Two experiments were performed to investigate the effect of different ratios of arginine (Arg) to lysine (Lys) in diets with low (30% Lys; Experiment 1) and high (45% Lys; Experiment 2) methionine (Met) levels on selected metabolic parameters, oxidative and epigenetic DNA damage, and the mechanisms underlying intestinal barrier integrity in turkeys challenged with Clostridium perfringens. In each experiment, 108 one-day-old Hybrid Converter female turkeys were placed in 6 pens (18 birds per pen) and reared for 42 days. At 34, 36 and 37 days of age, half of the birds were subjected to C. perfringens challenge. A 3 × 2 factorial design with three levels of Arg relative to Lys (90, 100 and 110%; Arg₉₀, Arg₁₀₀ and Arg₁₁₀, respectively) and C. perfringens infection (-, +) was employed. Challenging birds with C. perfringens increased lipid oxidation and the oxidation and methylation of DNA of intestinal mucosa, and down-regulated the activities of DNA-repairing enzymes. Neither the dietary treatment nor the challenge affected the markers of liver function or metabolism. Arg₁₁₀ diets with the high Met level induced DNA oxidation and methylation whereas these processes were downregulated in birds fed Arg₉₀ diets. The results indicate that Arg₉₀ diets with high Met levels have a beneficial influence on the indicators of intestinal barrier integrity in turkeys with necrotic enteritis (NE). Despite the analyzed amino acid ratios interacted with the systems responsible for the maintenance of gut integrity in the host organism, this dietary intervention probably enabled birds to cope with NE.

Effect of Amniotic Injection of N-Carbamylglutamate on Meat Quality of Broilers

Simple Summary

N-carbamylglutamate (NCG) is a key activator of endogenous arginine production, which plays a vital role in meat quality and antioxidant performance. To the best of our knowledge, there is no study about NCG enhancing the meat quality of broilers. The present research was aimed at exploring the effects of amniotic injection of NCG on meat quality of pectoral muscle in broilers. The data showed that the in ovo feeding (IOF) of NCG enhanced the arginine content, improved the nutritional properties, enhanced the antioxidant capacity, and improved the meat quality in the pectoral muscle of broilers. In summary, amniotic injection of NCG on day 17.5 of incubation could be an effective and novel approach to improving the meat quality of broilers.

Abstract

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

Effect of In Ovo Injection of L-Arginine in Different Chicken Embryonic Development Stages on Post-Hatchability, Immune Response, and Myo-D and Myogenin Proteins

Simple Summary

In the current study, we hypothesized that the in ovo injection of L-arginine (L-Arg) at different stages of embryonic development, which would have positive effects on the survival rate, hatching rate, immunoglobulin M (IgM) levels, heat shock proteins (HSPs) such as HSP-47, HSP-60, and HSP-70, and muscle development markers as well: Mainly, myoblast determination protein (myoD) and myogenin in pectoral muscles. As indicated, the in ovo injection of L-Arg resulted in an increased hatch rate and weight, survival rate, higher levels of IgM, and myogenin and MyoD expression in the muscles. At the same time, a decrease in the level of HSP-47, HSP-60, and HSP-70 expressions in the tissues was observed on the 14th day of injection compared to the eighth and 18th day of the injection period. In addition, the in ovo injection of L-Arg decreased the serum glutamate oxaloacetate transaminase (SGOT) and serum glutamate pyruvate transaminase (SGPT) concentration in serum as well micronuclei and nuclear abnormality in the blood on the 14th day of the incubation period. Hence, the 14th day would be a suitable day for the injection of L-Arg to promote the hatching rate and muscle growth of broiler chickens.

Abstract

The aim of this study was to evaluate the effect of in ovo injection with different ratios of L-arginine (L-Arg) into Ross broiler eggs at three different embryonic developmental stages (eighth day (d), 14th day, and 18th day) on the survival, hatchability, and body weight (BW) of one-day-old hatched chicks. Additionally, we have analyzed the levels of serum glutamate oxaloacetate transaminase (SGOT) and serum glutamate pyruvate transaminase (SGPT), the protein expression of heat shock proteins (HSPs), and we have also determined micronuclei (MN) and nuclear abnormality (NA). In addition, the genotoxic effect was observed in peripheral blood cells such as the presence of micronuclei and nuclear abnormalities in the experimental groups. The results showed that survival and hatching rates as well as body weight were increased on the 14th day of incubation compared to the eighth and 18th day of incubation at lower concentrations of L-Arg. Moreover, the levels of SGOT and SGPT were also significantly (p < 0.05) increased on the 14th day of incubation at the same concentration (100 μg/μL/egg) of injection. In addition, immunoglobulin (IgM) levels were increased on the 14th day of incubation compared to other days. The protein expressions of HSP-47, HSP-60, and HSP-70 in the liver were significantly down-regulated, whereas the expression of myogenin and myoblast determination protein (MyoD) were significantly up-regulated on the 14th day after incubation when treated with all different doses such as 100 μg, 1000 μg, and 2500 μg/μL/egg, namely 3T1, 3T2, and 3T3, respectively. However, the treatment with low doses of L-Arg down-regulated the expression levels of those proteins on the 14th day of incubation. Histopathology of the liver by hematoxylin and eosin (H&E) staining showed that the majority of liver damage, specifically intracytoplasmic vacuoles, were observed in the 3T1, 3T2, and 3T3 groups. The minimum dose of 100 μg/mL/egg on the 14th day of incubation significantly prevented intracytoplasmic vacuole damages. These results demonstrate that in ovo administration of L-Arg at (100 μg/μL/egg) may be an effective method to increase chick BW, hatch rate, muscle growth-related proteins, and promote the immune response through increasing IgM on the 14th day of the incubation period.

Effect of dietary arginine to lysine ratios on productive performance, meat quality, plasma and muscle metabolomics profile in fast-growing broiler chickens

Background

Due to the important functions of arginine in poultry, it should be questioned whether the currently adopted dietary Arg:Lys ratios are sufficient to meet the modern broiler requirement in arginine. The present study aimed, therefore, to evaluate the effects of the dietary supplementation of L-arginine in a commercial broiler diet on productive performance, breast meat quality attributes, incidence and severity of breast muscle myopathies and foot pad dermatitis (FPD), and plasma and muscle metabolomics profile in fast-growing broilers.

Results

A total of 1,170 1-day-old Ross 308 male chicks was divided into two experimental groups of 9 replicates each fed either a commercial basal diet (CON, digestible Arg:Lys ratio of 1.05, 1.05, 1.06 and 1.07 in each feeding phase, respectively) or the same basal diet supplemented on-top with crystalline L-arginine (ARG, digestible Arg:Lys ratio of 1.15, 1.15, 1.16 and 1.17, respectively). Productive parameters were determined at the end of each feeding phase (12, 22, 33, 43 d). At slaughter (43 d), incidence and severity of FPD and breast myopathies were assessed, while plasma and breast muscle samples were collected and analyzed by proton nuclear magnetic resonance-spectroscopy. The dietary supplementation of arginine significantly reduced cumulative feed conversion ratio compared to the control diet at 12 d (1.352 vs. 1.401, P < 0.05), 22 d (1.398 vs. 1.420; P < 0.01) and 33 d (1.494 vs. 1.524; P < 0.05), and also tended to improve it in the overall period of trial (1.646 vs. 1.675; P = 0.09). Body weight was significantly increased in ARG compared to CON group at 33 d (1,884 vs. 1,829 g; P < 0.05). No significant effect was observed on meat quality attributes, breast myopathies and FPD occurrence. ARG birds showed significantly higher plasma concentration of arginine and leucine, and lower of acetoacetate, glutamate, adenosine and proline. Arginine and acetate concentrations were higher, whereas acetone and inosine levels were lower in the breast of ARG birds (P < 0.05).

Conclusions

Taken together, these data showed that increased digestible Arg:Lys ratio had positive effects on feed efficiency in broiler chickens probably via modulation of metabolites that play key roles in energy and protein metabolism.

Nutritional requirements of meat-type and egg-type ducks: what do we know?

The demand for duck meat, duck eggs, and associated products is increasing each year. Classic and modern selection programs have been applied to enhance the economic traits of ducks to satisfy the requirements of consumers and enhance the incomes of producers. The nutritional requirements of unselected ducks may not be adequate, however, to fulfill the potential productivity performance of modern birds, including both meat-type and egg-type ducks. In particular, an imbalanced diet is associated with low productive performance and signs of nutritional deficiency (if insufficient nutrients are supplied), as well as with high feed costs and manure problems that reflect flock health and welfare (if excessive nutrients are supplied). Thus, the main aim of this review is to summarize the results of previous studies that estimated the nutrient requirements of meat-type and egg-type ducks in order to evaluate current knowledge and to identify further issues that need to be addressed. In addition, the results obtained in previous studies are compared in order to understand how to lower commercial feed costs, fulfill the genetic potential of selected ducks, protect the environment from pollution, and satisfy the welfare and health needs of ducks.

Nutritional factors affecting abdominal fat deposition in poultry: a review

The major goals of the poultry industry are to increase the carcass yield and to reduce carcass fatness, mainly the abdominal fat pad. The increase in poultry meat consumption has guided the selection process toward fast-growing broilers with a reduced feed conversion ratio. Intensive selection has led to great improvements in economic traits such as body weight gain, feed efficiency, and breast yield to meet the demands of consumers, but modern commercial chickens exhibit excessive fat accumulation in the abdomen area. However, dietary composition and feeding strategies may offer practical and efficient solutions for reducing body fat deposition in modern poultry strains. Thus, the regulation of lipid metabolism to reduce the abdominal fat content based on dietary composition and feeding strategy, as well as elucidating their effects on the key enzymes associated with lipid metabolism, could facilitate the production of lean meat and help to understand the fat-lowering effects of diet and different feeding strategies.