Juvenile rainbow trout (Oncorhynchus mykiss) performance in response to various ideal dietary amino acid patterns

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1 International Journal of Agriculture and Crop Sciences. Available online at IJACS/2013/5-22/ ISSN X 2013 IJACS Journal Juvenile rainbow trout (Oncorhynchus mykiss) performance in response to various ideal dietary amino acid patterns Rohallah Hemati Matin 1*, Zhaleh Khoshkhoo 1, Abbas Ali Motalebi 1 and Yavar Mahmoudi 2 1. Department of Fisheries, Faculty of Natural Resources, Islamic Azad University of North Tehran Branch-Iran 2. Department of Fisheries, Islamic Azad University, Ahvaz Branch, Iran Corresponding author Mattin_78@yahoo.com ABSTRACT : This study was carried out to investigate the juvenile rainbow trout performance in response to different ideal amino acid (IAA) ratios. A total of 1,200 juvenile rainbow trout were divided into 6 dietary treatments with 4 replications of 50 juveniles in each. The experimental diets were including a positive control (T1), a commercial diet (T2), and 4 treatments were formulated based on the IAA ratios recommended by (T3, T4, T5, and T6) 1. The results revealed that T1 and T2 promoted higher body weight gain (BWG) compared to the other semi-purified diets (P < 0.05). The best feed conversion ratio (FCR) was also determined for T5 (P < 0.05). The results of current study have shown that T5 IAA ratios had more efficiency to formulate juvenile rainbow trout diets than other tested IAA patterns. Based on these results, the promising potential of IAA profile in dietary protein reduction is relatively confirmed and consequently this concept, regarding the feed significant economical portion, it could be suggested as an effective tool for proper management which is worthy and needs intensive research in the future. Keywords: ideal amino acid; performance; rainbow trout; synthetic amino acids Abbreviations: Amino Acids (AAs); Body Weight Gain (BWG); Condition Factor (CF), Essential AAs (EAAs); Feed Conversion Ratio (FCR); Feed Intake (FI); Ideal Amino Acid (IAA); Non-essential AAs (NEAAs); Thermal-unit Growth Coefficient (TGC) INTRODUCTION The protein (amino acids, AAs) is the most expensive dietary macronutrient which directly affect fish performance (Abdelghany, 2000; Ng et al., 2001). The AAs requirements are usually done through doseresponse studies which are costly and time consuming (Akiyama et al., 1997). The concerns about the environmental effects of animal productions lead to addition of environmental factors (nitrogen and phosphorus pollutions) in feed formulation schemes. The ideal protein (ideal amino acid, IAA) concept provide a precise ratios of AAs and minimize nitrogen excretion. Therefore, it can play integral role in precision nutrition. Essential AAs (EAAs) cannot be synthesized in sufficient quantities in the body and must be included in the diet (McDonald, 2002). Non-essential AAs (NEAAs) can be synthesized in the body at higher rates and are not individually required in specific dietary concentrations (McDonald, 2002; Horton et al., 1996). However, all 20 common AAs are essential for protein synthesis and other functions, whether they are derived from the diets or are synthesized within the body (Harper, 1974). Various factors (age, diet protein, energy content and environmental variables) affect AAs requirements for maximum growth response of a given animal species (Fuller, 1994; Cowey, 1994; Boisen et al., 2000). Although, AAs requirements (as a proportion of the diet) vary according to mentioned factors, optimum relative proportions of the different AAs remain relatively constant (Cole et al., 1994; Boisen et al., 2000). Therefore, as total protein needs change, individual AAs need change proportionately. According to the ideal protein concept, optimum dietary EAAs quantities are considered as proportions relative to one another. The determination of optimum dietary AAs pattern allows the formulation of diets differ in protein content for a variety of age classes (Boisen et al., 2000). The optimum AAs pattern can be defined as a dietary AAs pattern in which each EAA is equally limiting to protein accretion (Wang and Fuller, 1 - T3, T4, T5, and T6: Ogino (1980), Webster (2002), NRC (1993) and Rodehutscord et al. (1995a, b, 1997), respectively.

2 1989). Although, AAs requirements change due to mentioned factors, ideal ratios would not change according to IAA concept. Some ideal AAs patterns was proposed for limited number of fishes such as rainbow trout (Ogino, 1980), catla (Ravi and Devaraj, 1991), chinook salmon, channel catfish, common carp, Japanese eel, and Nile tilapia (Nutrition, 1993). But, little scientific research and comparison were done between proposed IAAs ratios in rainbow trout (Oncorhynchus mykiss). Therefore, the current study was conducted to investigate some IAAs patterns on juvenile rainbow trout performance in Iranian farm aquaculture. MATERIAL AND METHODS Fish and Diets A total of 1,200 juvenile rainbow trout (Oncorhynchus mykiss) were randomly allocated to 6 treatments with 4 replications of 50 fishes in each at a completely randomized design. A diet was used as control (T1) to meet the nutrients requirements of fishes as positive control (Nutrition, 1993) (Table 1). Also, a commercial farm fish diet (T2) (prepared from local factory) was used to better comparison. Other treatments were formulated to meet the EAA patterns of rainbow trout reported by other (Ogino, 1980) (T3); (Webster, 2002) (T4); (Nutrition, 1993) (T5), and (Rodehutscord et al., 1995a, b, 1997) (T6), respectively (Table 3). The AAs contents of corn and fish meal were analyzed by HPLC (Tecator (Optimal 5931 Liquid Chromatography)) (Table 4) and then digestible contents of AAs was calculated using reported AAs digestibility coefficients (Nutrition, 1993). Synthetic AAs were used to exactly meet the AAs requirements in each profile. All AAs supplied as L-isomers except methionine which was supplied as DL-isomers. Except the control diet all diets were isoenergy (4,000 kcal metabolisable energy) and isoprotein (32.2% of diet) (Table 5 and 6). Where Rodehutscord (1995a, b, 1997) did not report recommendations for phenylalanine or tyrosine, dietary levels of these AAs were derived from NRC requirements. The amount of lysine 2.3 % was used to calculation (Encarnacao, 2005). Feed rations were arranged to 60 days of age. Moreover, body weight gain (BWG), feed intake (FI), feed conversion ratio (FCR), liver weight, Condition Factor (CF), and Thermal-unit Growth Coefficient (TGC) were measured. Feeding and Maintenance of Fish In this study, rainbow trout (10 ± 0.2 g) juveniles were stocked at the in density of 50 per tank in 24 ponds (660 liters). All ponds were supplied with 180 liters per minute river water. Fish were fed three times a day (morning, mid-day and afternoon), 5-6 days per week for the experiment period (12 days for adaptation). Fish were fed to near-satiation for the first 3 days of each week, for the last days of the week, feeding amount were adjusted so that all ponds received the same amount over the 5-6 day period as a percent of initial pond biomass. This adjusted amount was based on the amount of feed fed to the pond of fish which ate the least feed during the first 3 days of near-satiation feeding. This feeding method was employed to feed all fish tanks the same amount of feed, while feeding the most possible feed which would be eaten promptly by fish in all tanks. Fish in each tank were bulk weighed at 2 weeks intervals. Calculations All performance variables were calculated as following: BWG = the final weight gain the initial weight gain Daily Growth Rate= (BWf BWi) / N FCR= FI / BWG TGC= (100 (FBW1/3 IBW1/3)/ (Temp ( C)) days) CF= (W/L³) 100 Where: BWG: Body weight gain; BWf: Body weight final; W=Weight; BWi: Body weight initial; N: Number of rearing days; FBW: final body weight; IBW: initial body weight; Temp ( C): water temperature; days is the period under study in days; L: Total length; Statistical analysis A completely randomized design was employed for the experimental design. One-way analysis of variance was performed using the general linear model procedure of SAS software (SAS Institute, 2004). Duncan s multiple range test was used for the mean comparison (P 0.05). RESULTS The juvenile rainbow trout performance in response to different treatments are presented at Table 7. The results showed that significantly higher FI was obtained by T1 (commercial diet) which was not differ by 2704

3 treatments 2, 3, and 5. Also, the lowest FI was related to T6 which was not differ with T4. Treatments 1 and 2 had higher body BWG rather than semi-purified diets. Moreover, the lowest BWG was associated to T6 which did not differ with T4. The highest final BWG based on IAAs diets was related to T5 (NRC pattern). Furthermore, the highest FCR was observed by T6 and T4. The TGC, CF, and liver weights parameters are illustrated at Table 8. The highest amount of TGC was observed by T1 which did not differ with T2. Also, T6 induced the lowest TGC in this regards. The CF was significantly affected by dietary treatments. The results showed that T1 led to the highest CF which did not differ with T3 and T5. Also, T4 and T6 significantly induced the highest liver percent. DISCUSSION The numerous studies investigated low crude protein diets supplemented with crystalline AAs. A decrease in young chick performance with the decrease of dietary protein was found which not compensate by AA supplementation (Pinchasov et al., 1990; Holsheimer and Janssen, 1991; Kerr and Kidd, 1999). The low protein AA-supplemented diets led to lower performance in this study. It might be mainly attributed to lower FI due to lower texture and palatability of such conventional diets. The incorporation of crystalline-aas in the diets compared to protein-bound AAs lead to lower performance in different fish species (Mambrini and Kaushik, 1994; Rodehutscord et al., 1995, 1997; Zarate et al., 1999; Peres and Oliva-Teles, 2005). Inversely, supplementation of AAs-deficient diets with crystalline- AAs improve fish growth and feed utilization efficiency ( Robinson, 1991; Takagi et al., 2001; Cheng et al., 2003a, b).the lower utilization of crystalline-aas rather than protein-bound AAs attributed to crystalline-aas leaching, poor diet palatability or different patterns of AAs absorption. In fact, crystalline-aas absorption must occur simultaneous with that of protein-bound AAs (Dabrowski and Dabrowska, 1981; Plakas and Katayama, 1981; Zarate et al., 1999). The poor growth performance of fish fed crystalline AAs-based diets was reported (Cowey and Luquet, 1983). The most significant differences in rainbow trout performance were observed by T6 between different ideal AAs ratios (the lowest FI, BWG, and the worst FCR). It seems that inappropriate ratios of lysine: leucine (100:189) and lysine: valine (100:128) in T6 are the main cause of lower performance in this treatment. Accounts of AA imbalances conventionally focus on the growth-depressing effects in animals (Harperand and Rogers, 1965; Tews et al., 1979). Thus, it was reported that that rats fed an imbalanced diet reduced their FI within 3-6 h (Harperand and Rogers, 1965). These results implied that the depression in FI was the primary event responsible to retardation of growth. It expects that AAs imbalance decrease dramatically protein utilization efficiency. AAs excess contributes to AAs imbalance and stimulate AAs catabolism pathway which will result in AA catabolism (Kumta et al., 1958). Also, it was demonstrated that diet supplementation with excess leucine inhibited response of chicks to first limiting AA and decreased efficiency of protein utilization (D'mello and Lewis, 1970). The high levels of dietary leucine due to high Lys: Leu ratio (100:189) caused the same reduction in FI, BWG and feed efficiency in this study. The results have shown that no significant differences were found between T5 and T3 (i.e. FI, FCR and BWG). It can be concluded that some of the ideal ratios in T6 might be over-estimated for supporting maximum BWG and feed efficiency and could be decreased the recommended levels by T3 without any negative effect. Fish show preference for diets with balanced EAA pattern over diets with unbalanced AAs pattern (Yamamoto et al., 2000). Moreover, both protein and AA levels affect voluntary fish FI (Fournier et al., 2002). Differences in AA absorption rate between crystalline and protein-bound AAs could have limited the efficiency of AAs utilization, increases the deamination of AAs (Dabrowski and Dabrowska, 1981; Moyano et al., 1991). It showed that histidine deficiency led to intermediate nitrogen (N) losses compared with other NEAA (Rollin et al., 2003). This is in contrast with mono-gastric animals where histidine is usually the NEAA whose deficiency leads to the lowest N losses (Heger and Frydrych, 1985; Wang and Fuller, 1989). It might be due to a situation of histidine deficiency, the nature of the protein synthesized changes to those with lower histidine concentrations and the muscle protein turnover is sufficient to supply the amount of needed histidine (Heger and Frydrych, 1985). Treatment 6 tempts higher liver weight in current study (Table 8). It may be attributed to higher level of leucine. It found that additional of AAs arrive in portal circulation after consumption of an imbalanced diet stimulate synthesis or suppress break down of protein in the liver which both of them will result in increase in liver weight and led to greater retention of the limited AAs (Harperand and Rogers, 1965). Greater liver weight is usually associated with lower feed efficiency which is matched with present study (Table 7). The effect of dietary protein on the hepatic activity of key enzymes involved in AA catabolism is relatively contradictory in fishes. For instance, low protein diets have been associated with high hepatic deamination and treansamination activities (Kim et al., 1992; Suárez et al., 1995) in rainbow trout. Dietary replacement of protein-bound AAs by crystalline-aas or dietary AAs imbalance affects specific activities of AAs catabolism enzymes (Moyano et al., 1991, Gómez-Requeni et al., 2003; Peres and Oliva-Teles, 2005). This phenomenon can affect cell proliferation and lead to higher liver weights. 2705

4 CONCLUSION The results of current study have shown that rainbow trout diets can formulate by ideal amino acid profiles and reduce protein levels as possible as. It seems that the NRC profile had better outcome on juvenile rainbow trout performance between tested profiles in Iran. The AAs imbalanced affect performance parameters immediately. Moreover, the ideal protein concept is much less time consuming and less costly procedure than determining individual AA requirements. REFERENCES Abdelghany AE Optimum dietary protein requirements for Oreochromis niloticus L. fry using formulated semi-purified diets. ed. Tilapia Aquaculture in the 21st Century. Proceedings from the 5th International Symposium on Tilapia Aquaculture, 2000, Akiyama T, Oohara I, Yamamoto T Comparison of essential amino acid requirements with A/E ratio among fish species (review paper). Fisheries Sci 63: Boisen S, Hvelplund T, Weisbjerg MR Ideal amino acid profiles as a basis for feed protein evaluation. 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5 Rodehutscord M, Becker A, Pack M, Pfeffer E Response of rainbow trout (Oncorhynchus mykiss) to supplements of individual essential amino acids in a semipurified diet, including an estimate of the maintenance requirement for essential amino acids. J Nutr 127: Rodehutscord M, Jacobs SP, Pfeffer E Free amino acids can replace protein-bound amino acids in test diets for studies in rainbow trout (Oncorhynchus mykiss). J Nut 125: Rollin X, Mambrini M, Abboudi T, Larondelle Y, Kaushik SJ The optimum dietary indispensable amino acid pattern for growing Atlantic salmon (Salmo salar L.) fry. Brit J Nut 90: SAS Institute SAS user s Guide. Statistics ed. Version SAS Institute Inc., Cary, NC. Suárez M, Hidalgo MC, Gallego MG, Sanz A, Delahiguera M Influence of the relative proportions of energy yielding nutrients on liver intermediary metabolism of the European eel. Comp Biochem Physiol Part A: Physiology 111: Takagi S, Shimeno S, Hosokawa H, Ukawa M Effect of lysine and methionine supplementation to a soy protein concentrate diet for red sea bream Pagrus major. Fisheries Sci 67: Tews JK, Kim Y, Harper AE Induction of threonine imbalance by dispensable amino acids: relation to competition for amino acid transport into brain. J Nut 109:304. Wang T, Fuller M The optimum dietary amino acid pattern for growing pigs. Brit J Nutr 62: Webster CD Nutrient Requirements & Feeding of Finfish for Aquaculture. Cabi. Yamamoto T, Shima T, Furuita H, Shiraishi M, Sachez-Vasques FJ, Tabata M Self-selection of diets with different amino acid profiles by rainbow trout (Oncorhynchus mykiss). Aquaculture 187: Zarate D, Lovell R, Payne D Effects of feeding frequency and rate of stomach evacuation on utilization of dietary free and proteinbound lysine for growth by channel catfish Ictalurus punctatus. Aquaculture Nutr 5: Table 1. The compositions of positive control diet (treatment 1) Ingredients (%) Corn grain Corn gluten Fish meal Fish oil 3.33 DCP Common salt 0.30 Vit-premix Min-premix L-Lysine- Hcl 0.63 L- Argenine 0.24 Total Di-calcium phosphate; 2- Mineral premix: Mn, 100 mg; Zn, 84.5 mg; Fe, 80 mg; Cu, 20 mg; I, 1.6 mg; Co, 0.5mg; Se, 0.20 mg/ kg of diet 3- Vitamin premix; Vitamin A, IU; Vitamin D3, 1800 IU; Vitamin E, 36 mg; Vitamin k3, 5 mg; Tiamin, 1.53 mg; pholic acid, 1.26 mg; B12, 0.02 mg; Biotin, 0.5 mg; Coline chloride, 1100 mg; Anti oxidant, 100 mg/ kg of diet. Table 2. The diet analysis of positive control (treatment 1) (% or saied) Items Digestible energy (Kcal) 4000 Protein Calcium 1.00 Phosphorus 0.68 Arginine 1.60 Histidine 0.74 Isoleucine 1.07 Leucine 1.43 Lysine 1.80 Methionine + Cysteine Phenylalanine + Tyrosine Threonine 0.88 Tryptophan 0.33 Valine : Methionine in cellular metabolism is used to synthesize cysteine; 2: Phenylalanine in cellular metabolism is used to synthesize tyrosine. Table 3. Amino acid rations used to diets formulation Amino acid Treatment 3 Treatment 4 Treatment 5 Treatment 6 Lysine Arginine Histidine Isoleucine Leucine Methionine + Cysteine Phenylalanine + Tyrosine Threonine Tryptophan Valine Treatment 3- Ogino (1980); Treatment 4- Webster (2002); Treatment 5- NRC (1993); Treatment 6- Rodehutscord et al. 2707

6 Table 4. Amino acids in diets ingredients (mg\g) (HPLC analysis) Amino acid Corn grain Corn gluten meal Fish meal Lysine Arginine Histidine Isoleucine Leucine Methionine Cysteine Phenylalanine Tyrosine Threonine Tryptophan Valine Table 5. Diets composition based on ideal amino acids ratios Ingredients (%) Treatment 3 Treatment 4 Treatment 5 Treatment 6 Corn grain Corn gluten Fish meal Fish oil DCP Common salt Vit- premix Min- premix L-Lysine-HCl L- Arginine L- Histidine L- Isoleucine L- leucine DL- Methionine + L- Cysteine L- Phenylalanine + L- Tyrosine L- Threonine L- Tryptophan L- Valine Total Treatment 3- Ogino (1980); Treatment 4- Webster (2002); Treatment 5-; NRC (1993); Treatment 6- Rodehutscord et al. 1- Di-calcium phosphate; 2- Mineral premix: Mn, 100 mg; Zn, 84.5 mg; Fe, 80 mg; Cu, 20 mg; I, 1.6 mg; Co, 0.5mg; Se, 0.20 mg/ kg of diet 3- Vitamin premix; Vitamin A, IU; Vitamin D3, 1800 IU; Vitamin E, 36 mg; Vitamin k3, 5 mg; Tiamin, 1.53 mg; pholic acid, 1.26 mg; B12, 0.02 mg; Biotin, 0.5 mg; Coline chloride, 1100 mg; Anti oxidant, 100 mg/ kg of diet. Table 6. Diets analysis based on ideal amino acids ratios % Treatment 3 Treatment 4 Treatment 5 Treatment 6 Digestible energy (Kcal) Protein Calcium Phosphorus Arginine Histidine Isoleucine Leucine Lysine Methionine + Cysteine Phenylalanine + Tyrosine Threonine Tryptophan Valine Treatment 3- Ogino (1980); Treatment 4- Webster (2002) ; Treatment 5-; NRC (1993); Treatment 6- Rodehutscord et al. Table 7. Juvenile rainbow trout performance in response to various treatments Treatment FI 1 Final WG 2 BWG FCR ± a ±36.70 a 73.14± a ± c ± a ±32.77 a 40.26± a 0.02± c ± a ±24.32 c 64.12± b ± b ± bc ±24.32 c 75.77± c ± a ± ab ± b ± b 0.03± c ± c ±22.13 d 91.96± c 0.09± a 1.39 SEM P-value > 0.001> 0.001> 2708

7 1- Feed intake; 2- Weight gain; 3- Feed conversion ratio; Treatment 1- Positive control; Treatment 2- Commercial farm feed; Treatment 3- Ogino (1980); Treatment 4- Webster (2002) ; Treatment 5-; NRC (1993); Treatment 6- Rodehutscord et al. Table 8. Juvenile rainbow trout liver weights, condition factor and thermal-unit growth coefficient affected by different treatments Treatment Liver weight CF 1 TGC ± b ± a ± a ± b ± b ± ab ± b ± ab ± c ± a ± c ± d ± b ± ab ± bc ± a ± c ± e SEM P Value > : Condition factor 2: Thermal-unit growth coefficient; Treatment 1- Positive control; Treatment 2- Commercial farm feed; Treatment 3- Ogino (1980); Treatment 4- Webster (2002) ; Treatment 5-; NRC (1993); Treatment 6- Rodehutscord et al. 2709