Growth and Diet Utilization in Pacu Piaractus mesopotamicus Using Soybean Replacement of Casein-Gelatin as Protein Source Maria Esther Palacios 1,3, Konrad Dabrowski, 1 and C.C. Kohler 2 1 The Ohio State University, School of Natural Resources, Columbus, Ohio, USA 2 Southern Illinois University, Carbondale, Illinois, USA 3 Universidad Nacional de San Marcos, Lima, Peru

Fish market in Iquitos, Peru Fish is an Important Protein Source in the Peruvian Amazon

Utilization of Plant Proteins by Pacu Camu-camu (Myrciaria dubia) Aguaje (Mauritia flexuosa) Maca (Lepidium meyenii)

Maca Aguaje Camu-camu Control Weeks Mean body weight (g) Growth Rate of Juvenile Pacu Fed Experimental Diets Supplemented (15%) With Different Plant Protein Sources Control semipurified diet = Casein (40%), gelatin (8%), wheat meal 15%-based

Body Weights and Food Conversion in Rainbow Trout and Pacu Juveniles After 4 Weeks of Feeding Histological Examination of digestive tract (intestine, liver, pancreas) (Ostaszewska et al. 2003) Mean weight Feed conversion Mean weight (fish, g) Feed conversion (feed/gain) Pacu Rainbow trout Initial weight Initial weight Dietary treatment ControlSBM SPC

Objectives u To develop a semipurified, casein-gelatin based diet that can be used in nutrient requirement study with Amazonian fish. u To examine the effects of practical diets containing soybean meal (SBM) and soy protein concentrate (SPC) on growth and feed utilization in pacu, Piaractus mesopotamicus.

Composition of Experimental Diets Control SPC (50 % SBM (50 % protein replaced) protein replaced) Casein Gelatin SPC SBM Dextrin CPSP* Major Ingredients * Soluble fish protein concentrate (Suprapeche, France) Cod liver oil 11%; lecithin 3%;vitamin mix 4%; mineral mix 3%;CMC 0.5%

Experimental Conditions u Fish: juvenile pacu, Piaractus mesopotamicus u Weight: 0.34 g ± 0.02 (35 fish/tank) u Design: 3 dietary treatments (3 rep.) u Feeding: 4 – 8 % BW/day (3 times/day) u Water temp.: 26 ± 0.27 o C u Period: 8 weeks

u Growth rate (every 2 weeks) u Feed utilization  Feed Conversion Ratio (FCR) FCR = food consumption (g) / body weight gain (g)  Protein Efficiency Ratio (PER) PER= Weight gain (g) / protein intake (g)  Net Protein Utilization (NPU) NPU(%)=Protein gain (g) / protein intake (g) x 100 u Diet and whole body composition Parameters Examined

Pictures of Facility, Fish, and Analysis of Fish Samples

Results

Protein LipidAsh Control SPC (50%CP) SBM (50%CP) Diets Proximate Composition of Experimental Diets (% Dry Matter)

Experimental diets ControlSPCSBM Mean weight (g) Growth Performance of Pacu After 8 Weeks of Feeding Initial weight Final weight

Time (week) 2468 FCR Control SPC SBM Feed Conversion Ratio (FCR) for Pacu in the Course of the Study

Rainbow trout Pacu FCR FCR Casein- gelatin (Control) 0.87 ± 0.02 b 0.76 ± 0.01 a SPC (50%CP) 1.07 ± 0.04 a 0.73 ± 0.01 a SBM (50%CP) 1.04 ± 0.01 a 0.61 ± 0.03 b Dietary treatments FCR: food consumption (g) / body weight gain (g) Means annotated with the same letter are not significantly different (P > 0.05) Feed Conversion Ratio (FCR) of Juvenile Pacu and Rainbow Trout Fed Four Experimental Diets for 8 Weeks

Protein Lipid Ash Control SPC (50%CP) SBM (50%CP) Diets Whole Body Proximate Composition (%Dry Matter) of Juvenile Pacu Fed Three Experimental Diets for 8 Weeks

Rainbow troutPacu PER NPUPER NPU Casein- gelatin 1.95 ± 0.05 a 26.9 ± 1.5 a 2.23 ± 0.03 b 27.7 ± 0.5 c (Control) SPC (50%CP) 1.77 ± 0.07 b 22.7 ± 1.1 b 2.59 ± 0.04 b 32.2 ± 0.6 b SBM (50%CP) 1.76 ± 0.02 b 24.5 ± 0.5 b 3.07 ± 0.27 a 41.8 ± 3.5 a Diets Utilization of a Semipurified, Casein-gelatin Based Diet and Diets With 50% Protein Replaced by Soybean Meal (SBM) or Soy Protein Concentrate (SPC). Eight Week Feeding Experiments at  C (Rainbow trout) or 26  C (Pacu, Piaractus mesopotamicus) PER = Weight gain / protein intake NPU (%) = Protein gain / protein intake

Protein Efficiency Ratios in Cultured Fishes A comparison of protein efficiency ratios in young fish when fed semipurified diets (C: casein, G: gelatin, WG: wheat gluten, % of diet) in five studies on different species. Rainbow trout (Lee et al., 2004, our laboratories), coho salmon (Luzzana et al., 1997), channel catfish (Buentello and Gatlin 2000), pacu 0.3 g initial weight (Palacios et al., 2004, diet contained also 10% casein hydrolysate), and pacu 4.3 g initial weight (Tesser et al., 2004). The highest PER values in a particular study are shown.

Conclusions u Soybean meal protein replacement in casein gelatin based diets has significant positive effect on growth of pacu. u Pacu better utilize high protein diets containing plant protein sources compared to other species, such as salmonids and channel catfish.

Funding for this research was provided by the Aquaculture Collaborative Research Support Program The Aquaculture CRSP is funded in part by United States Agency for International Development (USAID) Grant No. LAG-G and by participating institutions.