METABOLISM AND NUTRITION Arginine affects appetite via nitric oxide in ducks C. Wang,*† S. S. Hou,* W. Huang,* T. S. Xu,‡ g. H. Rong,* and M. Xie*1 *Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100193, People’s Republic of China; †Chongqing Academy of Animal Sciences, Chongqing, 402460, People’s Republic of China; and ‡Tropical Crops Genetic Resources Research Institute, Chinese Academy of Tropical Agricultural Sciences, Danzhou, 571737, Hainan, People’s Republic of China 11-d-old ducks were allotted to 1 of 2 treatments. After 2 h fasting, birds in the 2 groups were intraperitoneally administrated saline and l-Ng-nitro-arginine methyl ester HCl (L-NAME) for 3 d, respectively. Feed intake (P < 0.07) and plasma nitric oxide concentration (P < 0.05) 2 h postinjection in the L-NAME administered group were lower than those of the control group. In conclusion, the study implied that arginine modifies feeding behavior possibly through controlling endogenous synthesis of nitric oxide in Pekin ducks.
Key words: duck, arginine, appetite, nitric oxide 2014 Poultry Science 93:1–6 http://dx.doi.org/10.3382/ps.2013-03812
INTRODUCTION
Meininger, 2002). Available evidence indicates that nitric oxide might be involved in mechanisms regulating feeding behaviors of animals. The orexigenic effect of neuropeptide Y, ghrelin, orexin A, and morphine in rats was attenuated by inhibition of endogenous nitric oxide synthesis via peripheral or central administration of nitric oxide synthase inhibitor l-Ng-nitro-arginine methyl ester HCl (L-NAME; Calignano et al., 1993; gaskin et al., 2003; Farr et al., 2005; Taksande et al., 2011). Administration of L-NAME inhibited the feed intake of broiler chickens, the anorectic effect was attenuated by intracerebroventricular administration of l-arginine (Choi et al., 1994). It was speculated that dietary arginine may regulate feed intake via the nitric oxide pathway in ducks. Therefore, the objective of the study was to estimate whether dietary arginine affects feeding behaviors via the nitric oxide pathway in ducks.
Arginine is a basic amino acid that is abundant in physiological fluids and body issue and has multiple physiological effects. Dietary arginine supplementation can increase muscle gain, reduce body fat mass, elevate protein and fat content in muscle (Fernandes et al., 2009; Tan et al., 2009; Wu et al., 2011), enhance immunity (Munir et al., 2009), improve embryonic survival and birth litter size (Mateo et al., 2007), and be beneficial to wound healing (Yu et al., 2001; Witte and Barbul, 2003) in animals. Conversely, dietary arginine deficiency impairs appetite and thus inhibits growth and development in pigs (Southern and Baker, 1983) and broiler chickens (Kidd et al., 2001; Labadan et al., 2001; Kwak et al., 1999). Our reports have shown that low dietary arginine decreases feed intake, especially from 1 to 21 d of age (up to 39%) in ducks (Wang et al., 2013a,b). However, the reason why feed intake is depressed by arginine deficiency is not completely clear. Arginine is the nitrogenous precursor for the endogenous synthesis of nitric oxide by nitric oxide synthase (Wu et al., 2009); increasing arginine concentration promotes nitric oxide synthesis in a variety of cells (Arnal et al., 1995; Wu et al., 1999; Wu and
MATERIALS AND METHODS The present research was approved by the animal care and welfare committee of the Institute of Animal Sciences in the Chinese Academy of Agricultural Sciences.
Experiment 1
©2014 Poultry Science Association Inc. Received December 6, 2013. Accepted May 6, 2014. 1 Corresponding author: [email protected]
One hundred forty-four 1-d-old male Z4 White Pekin ducks obtained from the Pekin duck breeding center 1
Downloaded from http://ps.oxfordjournals.org/ at Universite Laval on July 16, 2014
ABSTRACT The objective of the study was to investigate the mechanism by which arginine regulates feed intake in Pekin ducks. In experiment 1, one hundred forty-four 1-d-old male Pekin ducks were randomly allotted to 3 dietary treatments with 6 replicate pens of 8 birds per pen. Birds in each group were fed a corncorn gluten meal diet containing 0.65, 0.95, and 1.45% arginine. Ducks fed the diet containing 0.65% arginine had lower feed intake and plasma nitric oxide level (P < 0.05) than the other 2 groups. In experiment 2, twenty
2
Wang et al.
Table 1. Ingredient composition and nutrient content of the basal diet in experiment 1 (%, as-fed basis) Item
Value
Ingredient Corn Corn gluten meal Limestone Calcium phosphate Mineral and vitamin premix1 Sodium chloride l-Lysine·HCl dl-Methionine l-Tryptophan l-Threonine Calculated nutrient content ME2 (kcal/kg) Calcium Total phosphorus Available phosphorus Analyzed composition CP Lysine Methionine Cysteine Threonine Tryptophan Arginine
72.02 23.00 0.80 1.80 1.00 0.30 0.89 0.02 0.10 0.07 3.29 0.74 0.62 0.45 21.36 1.07 0.39 0.36 0.75 0.22 0.66
1Premix supplied per kilogram of diet: 10 mg of Cu, 60 mg of Fe, 60 mg of Zn, 80 mg of Mn, 0.3 mg of Se, 0.2 mg of I, 10,000 IU of vitamin A, 3,000 IU of vitamin D3, 20 IU of vitamin E; 2 mg of vitamin K3, 2 mg of thiamine, 8 mg of riboflavin, 4 mg of pyridoxine hydrochloride, 0.06 mg of cobalamin, 20 mg of pantothenic acid, 50 mg of nicotinic acid, 1 mg of folic acid, 0.2 mg of biotin, and 1,000 mg of choline chloride. 2The values are calculated according to the AME of ducks.
Table 2. Ingredient composition and nutrient content of the experimental diet in experiment 2 (%, as-fed basis) Item
Value
Ingredient Corn Corn gluten meal Limestone Calcium phosphate Mineral and vitamin premix1 Sodium chloride l-Lysine·HCl dl-Methionine l-Tryptophan l-Threonine l-Arginine·HCl Calculated nutrient content ME2 (kcal/kg) Calcium Total phosphorus Available phosphorus Analyzed composition CP Lysine Methionine Cysteine Threonine Tryptophan Arginine
71.65 23.00 0.80 1.80 1.00 0.30 0.89 0.02 0.1 0.07 0.37 3.28 0.74 0.62 0.45 21.70 1.09 0.41 0.36 0.76 0.22 0.98
1Premix supplied per kilogram of diet: 10 mg of Cu, 60 mg of Fe, 60 mg of Zn, 80 mg of Mn, 0.3 mg of Se, 0.2 mg of I, 10,000 IU of vitamin A, 3,000 IU of vitamin D3, 20 IU of vitamin E; 2 mg of vitamin K3, 2 mg of thiamine, 8 mg of riboflavin, 4 mg of pyridoxine hydrochloride, 0.06 mg of cobalamin, 20 mg of pantothenic acid, 50 mg of nicotinic acid, 1 mg of folic acid, 0.2 mg of biotin, and 1,000 mg of choline chloride. 2The values are calculated according to the AME of ducks.
pan) according to the method recommended by the Standardization Administration of China (2000). Throughout the experimental period, preweighed feed was given to each bird at 0800 h, and the remaining feed was weighed at 0800 h on the next day before new feed was added. Daily feed intake was calculated by subtracting the remaining feed from the total feed provided each day. At 21 d of age, 2 ducks with average BW of corresponding pens were selected and blood was collected from heart into tube containing 1% heparin, centrifuged at 1,520 × g for 10 min at 4°C; then the supernatant was collected for determination of nitric oxide concentration. Nitric oxide was determined by Nitrate Reductase Kit (Nanjing Jiancheng Bioengineering Institute, China) according to the manufacturer’s instructions.
Experiment 2 Twenty White Pekin Ducks that were 9 d old were selected and individually reared in plastic-wire-floor pens in an environmentally controlled experimental building. After 2 d of adaptation, birds were divided into 2 treatment groups. After 2 h fasting, the control and test group were intraperitoneally administrated saline or L-NAME (Sigma-Aldrich, St. Louis, MO) for 3 d, respectively. Prior to administration, L-NAME was dissolved into saline. The injected dose was 100 mg of
Downloaded from http://ps.oxfordjournals.org/ at Universite Laval on July 16, 2014
in the Chinese Academy of Agricultural Sciences were randomly allocated to 3 dietary arginine treatments with 6 replicate pens of 8 birds per pen. Each treatment was fed 1 of 3 experimental diets containing 0.65, 0.95, or 1.45% arginine for 3 wk. The recommended dietary arginine for growing White Pekin ducks is 0.95% (Wang et al., 2013a), whereas 0.65 and 1.45% arginine are considered deficient and excessive levels of dietary arginine, respectively. The basal experimental diet was formulated using corn and corn gluten meal and contained 0.65% arginine. l-Arginine HCl (Huikangyuan Chemical, Beijing, China) replaced corn to obtain experimental diets containing 0.95 and 1.45% arginine. Except for the arginine content of the experimental diet, all nutrients meet the recommendations for ducklings from the Ministry of Agriculture of China (2012). The ingredient compositions and chemical analyses of the diets are shown in Table 1. Experimental birds were kept in plastic-wire-floor pens in an environmentally controlled duck house. The temperature was set at 28°C from 1 to 3 d of age, at 26°C from 4 to 7 d of age, at 25°C from 8 to 14 d of age, then keep at room temperature from 15 to 21 d of age. All birds had free access to pelleted feed, and drinking water and lighting were provided continuously. The amino acid contents of the experimental diets were analyzed by ion-exchange chromatography with an Amino Acid Analyzer (L-8900, Hitachi, Tokyo, Ja-
3
RESEARCH NOTE Table 3. Effect of arginine on feed intake of Pekin ducks from 1 to 21 d of age (g/bird per d)1 Age (d) Item Arginine level (%) 0.65 0.95 1.45 Pooled SEM P-value
1–7
8–14
15–21
1–21
21.8a 24.5b 25.2b 0.5 0.0053
46.0a 76.6b 76.4b 3.7
Key words: duck, arginine, appetite, nitric oxide 2014 Poultry Science 93:1–6 http://dx.doi.org/10.3382/ps.2013-03812
INTRODUCTION
Meininger, 2002). Available evidence indicates that nitric oxide might be involved in mechanisms regulating feeding behaviors of animals. The orexigenic effect of neuropeptide Y, ghrelin, orexin A, and morphine in rats was attenuated by inhibition of endogenous nitric oxide synthesis via peripheral or central administration of nitric oxide synthase inhibitor l-Ng-nitro-arginine methyl ester HCl (L-NAME; Calignano et al., 1993; gaskin et al., 2003; Farr et al., 2005; Taksande et al., 2011). Administration of L-NAME inhibited the feed intake of broiler chickens, the anorectic effect was attenuated by intracerebroventricular administration of l-arginine (Choi et al., 1994). It was speculated that dietary arginine may regulate feed intake via the nitric oxide pathway in ducks. Therefore, the objective of the study was to estimate whether dietary arginine affects feeding behaviors via the nitric oxide pathway in ducks.
Arginine is a basic amino acid that is abundant in physiological fluids and body issue and has multiple physiological effects. Dietary arginine supplementation can increase muscle gain, reduce body fat mass, elevate protein and fat content in muscle (Fernandes et al., 2009; Tan et al., 2009; Wu et al., 2011), enhance immunity (Munir et al., 2009), improve embryonic survival and birth litter size (Mateo et al., 2007), and be beneficial to wound healing (Yu et al., 2001; Witte and Barbul, 2003) in animals. Conversely, dietary arginine deficiency impairs appetite and thus inhibits growth and development in pigs (Southern and Baker, 1983) and broiler chickens (Kidd et al., 2001; Labadan et al., 2001; Kwak et al., 1999). Our reports have shown that low dietary arginine decreases feed intake, especially from 1 to 21 d of age (up to 39%) in ducks (Wang et al., 2013a,b). However, the reason why feed intake is depressed by arginine deficiency is not completely clear. Arginine is the nitrogenous precursor for the endogenous synthesis of nitric oxide by nitric oxide synthase (Wu et al., 2009); increasing arginine concentration promotes nitric oxide synthesis in a variety of cells (Arnal et al., 1995; Wu et al., 1999; Wu and
MATERIALS AND METHODS The present research was approved by the animal care and welfare committee of the Institute of Animal Sciences in the Chinese Academy of Agricultural Sciences.
Experiment 1
©2014 Poultry Science Association Inc. Received December 6, 2013. Accepted May 6, 2014. 1 Corresponding author: [email protected]
One hundred forty-four 1-d-old male Z4 White Pekin ducks obtained from the Pekin duck breeding center 1
Downloaded from http://ps.oxfordjournals.org/ at Universite Laval on July 16, 2014
ABSTRACT The objective of the study was to investigate the mechanism by which arginine regulates feed intake in Pekin ducks. In experiment 1, one hundred forty-four 1-d-old male Pekin ducks were randomly allotted to 3 dietary treatments with 6 replicate pens of 8 birds per pen. Birds in each group were fed a corncorn gluten meal diet containing 0.65, 0.95, and 1.45% arginine. Ducks fed the diet containing 0.65% arginine had lower feed intake and plasma nitric oxide level (P < 0.05) than the other 2 groups. In experiment 2, twenty
2
Wang et al.
Table 1. Ingredient composition and nutrient content of the basal diet in experiment 1 (%, as-fed basis) Item
Value
Ingredient Corn Corn gluten meal Limestone Calcium phosphate Mineral and vitamin premix1 Sodium chloride l-Lysine·HCl dl-Methionine l-Tryptophan l-Threonine Calculated nutrient content ME2 (kcal/kg) Calcium Total phosphorus Available phosphorus Analyzed composition CP Lysine Methionine Cysteine Threonine Tryptophan Arginine
72.02 23.00 0.80 1.80 1.00 0.30 0.89 0.02 0.10 0.07 3.29 0.74 0.62 0.45 21.36 1.07 0.39 0.36 0.75 0.22 0.66
1Premix supplied per kilogram of diet: 10 mg of Cu, 60 mg of Fe, 60 mg of Zn, 80 mg of Mn, 0.3 mg of Se, 0.2 mg of I, 10,000 IU of vitamin A, 3,000 IU of vitamin D3, 20 IU of vitamin E; 2 mg of vitamin K3, 2 mg of thiamine, 8 mg of riboflavin, 4 mg of pyridoxine hydrochloride, 0.06 mg of cobalamin, 20 mg of pantothenic acid, 50 mg of nicotinic acid, 1 mg of folic acid, 0.2 mg of biotin, and 1,000 mg of choline chloride. 2The values are calculated according to the AME of ducks.
Table 2. Ingredient composition and nutrient content of the experimental diet in experiment 2 (%, as-fed basis) Item
Value
Ingredient Corn Corn gluten meal Limestone Calcium phosphate Mineral and vitamin premix1 Sodium chloride l-Lysine·HCl dl-Methionine l-Tryptophan l-Threonine l-Arginine·HCl Calculated nutrient content ME2 (kcal/kg) Calcium Total phosphorus Available phosphorus Analyzed composition CP Lysine Methionine Cysteine Threonine Tryptophan Arginine
71.65 23.00 0.80 1.80 1.00 0.30 0.89 0.02 0.1 0.07 0.37 3.28 0.74 0.62 0.45 21.70 1.09 0.41 0.36 0.76 0.22 0.98
1Premix supplied per kilogram of diet: 10 mg of Cu, 60 mg of Fe, 60 mg of Zn, 80 mg of Mn, 0.3 mg of Se, 0.2 mg of I, 10,000 IU of vitamin A, 3,000 IU of vitamin D3, 20 IU of vitamin E; 2 mg of vitamin K3, 2 mg of thiamine, 8 mg of riboflavin, 4 mg of pyridoxine hydrochloride, 0.06 mg of cobalamin, 20 mg of pantothenic acid, 50 mg of nicotinic acid, 1 mg of folic acid, 0.2 mg of biotin, and 1,000 mg of choline chloride. 2The values are calculated according to the AME of ducks.
pan) according to the method recommended by the Standardization Administration of China (2000). Throughout the experimental period, preweighed feed was given to each bird at 0800 h, and the remaining feed was weighed at 0800 h on the next day before new feed was added. Daily feed intake was calculated by subtracting the remaining feed from the total feed provided each day. At 21 d of age, 2 ducks with average BW of corresponding pens were selected and blood was collected from heart into tube containing 1% heparin, centrifuged at 1,520 × g for 10 min at 4°C; then the supernatant was collected for determination of nitric oxide concentration. Nitric oxide was determined by Nitrate Reductase Kit (Nanjing Jiancheng Bioengineering Institute, China) according to the manufacturer’s instructions.
Experiment 2 Twenty White Pekin Ducks that were 9 d old were selected and individually reared in plastic-wire-floor pens in an environmentally controlled experimental building. After 2 d of adaptation, birds were divided into 2 treatment groups. After 2 h fasting, the control and test group were intraperitoneally administrated saline or L-NAME (Sigma-Aldrich, St. Louis, MO) for 3 d, respectively. Prior to administration, L-NAME was dissolved into saline. The injected dose was 100 mg of
Downloaded from http://ps.oxfordjournals.org/ at Universite Laval on July 16, 2014
in the Chinese Academy of Agricultural Sciences were randomly allocated to 3 dietary arginine treatments with 6 replicate pens of 8 birds per pen. Each treatment was fed 1 of 3 experimental diets containing 0.65, 0.95, or 1.45% arginine for 3 wk. The recommended dietary arginine for growing White Pekin ducks is 0.95% (Wang et al., 2013a), whereas 0.65 and 1.45% arginine are considered deficient and excessive levels of dietary arginine, respectively. The basal experimental diet was formulated using corn and corn gluten meal and contained 0.65% arginine. l-Arginine HCl (Huikangyuan Chemical, Beijing, China) replaced corn to obtain experimental diets containing 0.95 and 1.45% arginine. Except for the arginine content of the experimental diet, all nutrients meet the recommendations for ducklings from the Ministry of Agriculture of China (2012). The ingredient compositions and chemical analyses of the diets are shown in Table 1. Experimental birds were kept in plastic-wire-floor pens in an environmentally controlled duck house. The temperature was set at 28°C from 1 to 3 d of age, at 26°C from 4 to 7 d of age, at 25°C from 8 to 14 d of age, then keep at room temperature from 15 to 21 d of age. All birds had free access to pelleted feed, and drinking water and lighting were provided continuously. The amino acid contents of the experimental diets were analyzed by ion-exchange chromatography with an Amino Acid Analyzer (L-8900, Hitachi, Tokyo, Ja-
3
RESEARCH NOTE Table 3. Effect of arginine on feed intake of Pekin ducks from 1 to 21 d of age (g/bird per d)1 Age (d) Item Arginine level (%) 0.65 0.95 1.45 Pooled SEM P-value
1–7
8–14
15–21
1–21
21.8a 24.5b 25.2b 0.5 0.0053
46.0a 76.6b 76.4b 3.7
