EFFECTS OF NATURAL ZEOLITE (CLINOPTILOLITE) LEVELS IN GOLDFISH DIETS ON, GROWTH, WATER QUALITY AND DIGESTIBILITY OF THE COMMON GOLDFISH (Carassius auratus)
Zeolites are used in aquaculture to remove ammonium from hatcheries, reduce ammonia build up during fish transportation and recently as feed additives. The few studies investigating the use of dietary zeolite were conducted on aquaculture fish species: rainbow trout fed diets containing 2.5% zeolite showed lower total ammonia production compared to a control diet (Ergun et al. 2008) and improved growth of tilapia was found when fed diets containing 1 and 2% zeolite (Yildrim et al., 2009). Their findings presented an opportunity to evaluate whether zeolite could be used as a feed additive to improve growth, water quality and digestibility of a common ornamental fish species, the common goldfish (Carassius auratus).
This study investigated whether inclusions of zeolite (clinoptilolite at 0, 1, 2 and 4%) in commercially extruded goldfish diets fed to the common goldfish (Carassius auratus) had an effect on their growth (14 week feeding trial), water quality (30h without filtration) and digestibility of the diets (two-week faecal collection). Each trial diet was applied to triplicate groups of 10 common goldfish (mean wet mass 3.73Fish were fed twice daily for the feeding and digestibility trial, and fed five times over the 30hour period of the water quality trial.
The specific growth rate and feed conversion ratio of the common goldfish was not effected by dietary treatment (Table 2). Total ammonia nitrogen (TAN) and turbidity of tank water from goldfish fed zeolite diets was effected by dietary treatment (Table 2; TAN - F3,59=4.06, p<0.05; Turbidity - F3,59=3.02 p<0.05), whereby the 2% zeolite diet had significantly less total ammonia, and reduced turbidity compared to the diet containing no zeolite. Water colour was not significantly affected by diet (Table 1). Results from analysis of faecal samples for digestibility are still pending.
Lower ammonia release will benefit the fishs water quality, improving their welfare, whilst clearer water will create more aesthetically pleasing tanks for fish keepers. It was concluded that zeolite at 2% may be a suitable feed additive for use in goldfish diets to improve their water quality.
This study investigated whether inclusions of zeolite (clinoptilolite at 0, 1, 2 and 4%) in commercially extruded goldfish diets fed to the common goldfish (Carassius auratus) had an effect on their growth (14 week feeding trial), water quality (30h without filtration) and digestibility of the diets (two-week faecal collection). Each trial diet was applied to triplicate groups of 10 common goldfish (mean wet mass 3.73Fish were fed twice daily for the feeding and digestibility trial, and fed five times over the 30hour period of the water quality trial.
The specific growth rate and feed conversion ratio of the common goldfish was not effected by dietary treatment (Table 2). Total ammonia nitrogen (TAN) and turbidity of tank water from goldfish fed zeolite diets was effected by dietary treatment (Table 2; TAN - F3,59=4.06, p<0.05; Turbidity - F3,59=3.02 p<0.05), whereby the 2% zeolite diet had significantly less total ammonia, and reduced turbidity compared to the diet containing no zeolite. Water colour was not significantly affected by diet (Table 1). Results from analysis of faecal samples for digestibility are still pending.
Lower ammonia release will benefit the fishs water quality, improving their welfare, whilst clearer water will create more aesthetically pleasing tanks for fish keepers. It was concluded that zeolite at 2% may be a suitable feed additive for use in goldfish diets to improve their water quality.