INCORPORATION OF CITRUS PULP IN DIETS FED TO JUVENILE BUSHY-NOSED PLECO Ancistrus cirrhosus AS A LOCAL ALTERNATIVE TO TRADITIONAL FIBROUS CARBOHYDRATE SOURCES.    

Inclusion of locally available feedstuffs is essential to least-cost diet formulation and controlled, sustainable fish production.  Traditional studies on carnivorous fish have used regional feed ingredients where animal-based protein feed ingredients have been replaced with plant-based feedstuffs.  Similar attention investigating fishmeal alternatives for diets fed to herbivorous fish is less available, particularly for those commonly cultured for the aquarium trade, including species belonging to the genus Ancistrus.  A. cirrhosus, or bushy-nosed pleco, are a popular aquarium species whose production is significant to the Florida aquaculture industry.  

Commercially manufactured diets specifically formulated for pleco are limited.  Therefore, diets fed to pleco are generally commercial feeds for other more carnivorous species, or compressed wafers of algae which may not provide stuffiest nutrients for maximum growth in a production setting.  Reduced weight gain, decreased survival and skeletal abnormalities have been reported by producers using commercially formulated pleco diets; however, those diets contained a minimum level of crude fiber which may hinder digestion in this species.  The present study sought to investigate increasing dietary fiber in diets fed to pleco by using citrus pulp.

Citrus pulp is a byproduct of the citrus juice industry consisting of dried residue of peel, pulp and seeds.  Citrus pulp in an excellent source of carbohydrates, fiber and vitamin C.  In some agriculture industries dried citrus pulp is second only to corn as a source of concentrated feed nutrients.  Five experimental diets were formulated based on the known nutrient needs of pleco and those nutrient levels common in commercial feeds for herbivores.  Citrus pulp was used as a replacement for yellow dent corn in four experimental diets at an inclusion level of 10g pulp/100g diet to 40g pulp/100g diet.  The control diet contained no citrus pulp.  

Triplicate groups of fish were stocked into a recirculation system at a density of 5 pleco per gallon and fed their respective diets for eight weeks.  Weight gain, feed efficiency and skeletal condition were evaluated for each dietary treatment.  Results indicated that growth and feed efficiency of pleco fed diets containing 10g citrus pulp/100 g diet exhibited growth which was not significantly different than that of fish fed the control diet.  No skeletal abnormalities were noted in any treatment and no mortalities were observed.