No abstract

A study was conducted to compare growth and feed utilization of Oreochromis aureus fed graded levels of coffee pulp (CoP) and reared in aquaria or in pens. Diets contained 0, 130, 260 and 390 g kg À 1 of oven-dried CoP. In aquaria, fish receiving increasing dietary CoP levels (from 0 to 390 g kg À 1) showed a progressive reduction in final body weight, growth rate and protein efficiency ratio (PER) (P < 0.05). Feed conversion ratio (FCR) was significantly higher at 390 g kg À 1 dietary CoP. Dietary CoP reduced digestibility of dietary dry matter and carbohydrate. In pens, CoP inclusions led to reduced final weight, growth rate and PER but to a much smaller extent than in aquaria. Fish fed the diet with 130 g kg À 1 CoP had similar growth and feed utilization (PER and FCR) to those fed the control diet (P>0.05). High dietary fibre levels together with the presence of antinutritional factors (ANFs) in CoP diets may explain why tilapia grew less and had lower feed utilization. Natural productivity of the pond could explain why results in pens were better than in aquaria. Results indicated that inclusion of CoP in tilapia diets might be limited to no more than 130 g kg À 1 when fish are raised in earthen ponds and natural food is available.

No abstract

A feeding experiment was conducted to evaluate the growth of tiger guapote, Cichlasoma managuense (Gunther), fed on isocaloric diets with varying proteinxnergy ratios. The relative metabolic growth rate increased with the protein:energy ratio up to 110-120 mg protein/kcal {P < 0-05). The protein efficiency ratio was optimal at llOmg protein/kcal. The body composition was clearly influenced by diet composition. Results indicate that juvenile C managuense obtains near optimal growth rates when fed 35-40% protein diets with 110-120mg protein/kcal. Higher ratios will not be cost effective.

The proteolytic digestive activity and growth of Parachromis dovii larvae during the ontogeny were evaluated in a recirculation system using two feeding strategies during a 28-day period. Larvae were reared using two feeding protocols (three replicates each): (A) Artemia nauplii (at satiation), fed from exogenous feeding [8 days after hatching (DAH)] until 15 DAH followed by nauplii substitution by formulated feed (20% day(-1)) until 20 DAH and then formulated feed until 28 DAH; (B) formulated feed (100 % BW daily) from exogenous feeding until 28 DAH. Levels of acid (pepsin type) and alkaline digestive proteases as well as growth and survival of larvae were measured along the feeding period. Survival was high and similar between treatments: 98.9 ± 0.0 for Artemia, 97.3 ± 0.0% for formulated feed. The specific growth rate for length and weight was higher in larvae fed with Artemia nauplii than in larvae reared with formulated feed: 3.4 ± 0.1 versus 1.8 ± 0.1% day(-1) for body length (P = 0.009) and 12.2 ± 0.1 versus 6.5 ± 0.3% day(-1) for body weight (P = 0.002). The acid and alkaline proteolytic activity was detected, in both treatments, from the beginning of the experiment, at 8 DAH. The total enzymatic activity (U larva(-1)) for acid and alkaline proteases was higher in larvae reared with Artemia after 12 DAH, whereas the specific enzymatic activity was similar for both enzyme types in the two treatments. The results suggest that P. dovii larvae were capable to digest formulated diets from the beginning of exogenous feeding and that they could be reared with formulated feeds. However, the formulated feed used should be nutritionally improved because of the poor growth obtained in this research.