At the end of the red waste biotransformation an alga Gelidium agar -agar sesquipedale after extraction, we achieved a finished product free of pathogenic bacteria and rich in protein 26%, fat 0.40%, carbohydrate 38% and 11% minerals. Three diets containing respectively 20%, 25%, 30% seaweed waste are compared with a commercial ration to determine the best growth on sheep. We followed the weight gain and average daily gain during the 90 days. Four batches of ten sheep each were submitted to the fattening test. Lot 1 receiving the food (F1) reached an average gain resulting weight of 14.5 kg or average daily gain (ADG) of 161 g / d. Lot 2 receiving the food F2 recorded an average weight gain of 16.3 kg is the equivalent of a daily gain 181 g / d. As for lot3 nourished by the food F3, marked the largest average weight gain of 19.35 Kg, a daily gain of 215 g / d. The control group regarding showed him a mean weight gain of interest near that of lot1 13.3 Kg, which corresponds to an average daily gain of 147 g / d. In addition, microbiological analyzes of sheep carcasses and viscera showed that total mesophilic anaerobic flora varies between 102 and 103 cfu / g and faecal coliforms vary between 1 and 3 cfu / g. Salmonella and clostridia are totally absent. These results confirm the possibility of solving problems due to protein and mineral deficiencies in animals by adding these fermented waste and obtain a clean and healthy meat for consumption.