No abstract

Feeding experiments were conducted on large and small adult freshwater prawns Macrobrachium rosenbergii (36.96 ± 1.65 and 13.48 ± 1.65 g in weight) to determine the impact of dietary fiber on growth, digestion, and gastric emptying time. Fiber was incorporated as Q‐cellulose into four semi‐purified diets at calculated levels of 0, 5, 10 and 15% at the expense of starch and fed for an 8‐wk period. The experiment was conducted in a closed, filtered, recirculating freshwater system. The results indicate that the specific growth rates, feed conversion ratios, and protein efficiency ratios improved as the levels of dietary fiber increased from 0.4% to 8%. Gastric emptying times increased as the level of inclusion of cellulose in the diets increased. It was concluded that diets containing up to 10% dietary fiber increases growth rates in adult prawn Macrobrachium rosenbergii by increasing nutrient residence time in the gastrointestinal tract, thereby increasing absorption.

The feeding energetics of the prawn Macrobrachium rosenbergii (De Man 1879) were examined with respect to the effect of dietary fibre. Adult animals were fed semi‐purified diets with 0%, 5%, 10% and 15%α‐cellulose to determine the maximum aerobic scope that could be elicited by the increase in metabolism as specific dynamic action (SDA). The excretion rates of ammonia were also measured. Prawns fed all diets had significantly higher respiration rates after feeding due to SDA. Feed intake was not related to metabolism rate. Both oxygen uptake and ammonia excretion were affected by feed intake, dietary cellulose and time after feeding. SDA was related to dietary fibre, indicated by increments varying from 37% to 386%. O:N ratios were influenced by feed intake, dietary cellulose levels and time after feeding. O:N ratios of between 10 and 49 indicate that the prawns predominately metabolize carbohydrate.