An investigation into the effect of four Coppens’ fish diets on the growth, performance and feed utilisation of goldfish (Carassius auratus).
A feed trial was conducted to determine the performance of four Coppens commercial fish dietsfor ongrowing goldfish (C. auratus). The diet’s protein and lipid % inclusion rates were 33 and 6% Standard (S), 34 and 15% Basic Select (BS), 46 and 16% Supreme 16 (S16) and 42 and 18% Prime 18 (P18). The two low protein (30%) diets were marketed as carp diets and the two high protein (40%) diets were marketed as trout diets. Two hundred and forty goldfish (C. auratus) of 15gr (+/- 0.9gr) were randomly assigned to 12 aquaria (80 litres). Four diets varying from 14.12 – 17.23 MJ/kg were fed isocalorifically at 3 – 3.66 % body weight for a period of 8 weeks. The fish grew on average 115% (+/- 15%) of their original body weight (BW) at an average rate of 1.37 % (+/- 0.12%) BW per day. Basic Select (BS), Supreme 16 (S16) and Prime 18 (P18) had a highly significantly lower Food Conversion ratio (FCR) than the Standard (S) diet. (p<0.01) P18 had a significantly lower FCR than BS.(p<0.05) BS had a highly significantly higher PER than S and S16. (p<0.01) BS had a significantly higher Protein Efficiency ratio (PER) than P18. (p<0.05) P18 had a significantly higher PER than S and S16. (p<0.05) BS, S16 and P18 had a significantly higher Specific Growth rate (SGR) than diet S. (p<0.05) The S diet had the lowest economic benefits. The relative economic advantage of BS, S16 and P18 were 14, 16 and 20% respectively. The condition factor (CF) of the fish at the start of the trial was 1.78 (+/-0.11). There were no differences at the end averaging 1.73 (+/-0.09)
The experimental design and protocol is given below
This trial will be used to evaluate the suitability of four commercial feeds. Goldfish of an initial weight of approximately 15 grams (80-100mm) will be on-grown for a period of 4 weeks. (This maybe extended afterwards as a dissertation). Detailed analysis of growth and FCR will help to identify an optimum, economic level of protein and lipid incorporation. At the end of the feeding trial an assessment of the fish’s condition factor will help to establish whether the differences in formulation impact upon the desirability of the fish produced. The Students at Sparsholt College will be responsible for the routine husbandry of the fish and monitoring the feed intake, growth and FCR of the fish.
The key performance and quality indicators that will be measured are listed below:
- Growth (SGR)
- Feed conversion ratio (FCR)
- Protein efficiency ratio (PER)
- Condition factor (K)
Location and facilities
The trial will be undertaken using 12 indoor 80 litre aquaria run off a single recirculation system within the dissertation facility at the National Aquatics Centre, Sparsholt College, Hampshire.
4 diets will be fed to triplicate groups of goldfish. The key features of the four diets to be used in this trial are shown in Table 1.
The price of the diets will be given at the start of the trial.
240 Goldfish of approximately 10 grams (80-100mm) from Hampshire Carp Hatcheries own strain will be randomly distributed into12 tanks (20 per tank). During the trial period, the movement of the fish must be prevented i.e. fish must not be added to or taken from the tank and any treatments e.g. disease treatment must be undertaken for all tanks simultaneously.
Before the start of the trial, the fish will be fed to appetite on the Aquatic Centre’s standard cyprinid diet.
The fish will be fed at approximately 2% B.W. but the rations will be calculated isocalorifically. The isocalorific multiplication factor will be given to the students at the start of the trial. Each tank’s diet will be calculated and weighed out at the start of the week into daily feed dispensers. The fish will be fed twice daily approximately half morning and afternoon. Care must be taken in the feed distribution to ensure all of the feed is consumed.
The tanks will be sampled by bulk weight each week and rations calculated accordingly. At the end of the trial the fish will be individually weighed and lengthened to measure condition factor.
- Define dietary effects on growth and feed utilization.
- Define dietary effects on the condition factor.
- Calculate economic impacts of diets on production.