Different utilization of plant sources by the omnivores jundiá catfish (Rhamdia quelen) and Nile tilapia (Oreochromis niloticus)

Abstract

Plant sources are receiving special attention as feedstuffs in aquafeeds because of fish meal and oil shortage. However, studies about the effects of dietary fibre in fish are scarce. The inclusion of plant ingredients containing different levels of dietary fibre -broken rice (BR), ground corn (GC), wheat bran (WB), citrus pulp (CP) and soybean hulls (SH) were evaluated for the omnivores jundia´catfish and Nile tilapia. Tilapia is a typical omnivore with long intestines, whereas jundia´has short intestines and no pyloric ceca. Fibrous sources (CP, WB and SH) were less digestible for both species than the starchy ones (BR and GC). However, jundia´presented less ability to utilize the starch and protein from plant sources than tilapia. Growth of tilapia followed plant sources digestibility but no significant differences were detected for jundia´, probably because of its slower growth rate. Muscle layer was thicker in the distal intestine of jundia´fed CP diet, which possibly indicates an adaptation to propel the large volume of viscous digesta along the intestine. Therefore, despite its lower ability to utilize starchy plant sources, jundia´showed an adaptive capacity to utilize fibrous diets, which is in agreement with its omnivorous feeding habit.

Apparent Protein and Energy Digestibility and Amino Acid Availability of Corn and Co‐products in Extruded Diets for Nile Tilapia, Oreochromis niloticus

“…Zhou et al () found a lower ADCDM (84.6%), but similar ADCGE (94.2%) and ADCCP (94.4%) for corn gluten meal fed to cobia, Rachycentron canadum . It is more difficult for carnivorous fish and omnivores with carnivorous tendencies to digest plant‐derived nutrients than it is for herbivorous fish or omnivores with herbivorous tendencies (NRC ; Rodrigues et al ). Levels of amylolytic and proteolytic activity in the digestive tract vary widely among fish with different feeding habits (Hidalgo et al ), which reflects differential ability to digest energy and nutrients from plant materials (Bakke et al ).…”

Replacement of animal protein sources by soy protein concentrate for juvenile Nile tilapia

“…Nile tilapia is a typical omnivore, with long intestines and physiological adaptations to tolerate higher inclusion of dietary plant sources (RODRIGUES et al, 2012;GOMINHO-ROSA et al, 2014). Soy protein concentrate has higher protein and lower carbohydrate contents than ordinary soybean meal but still showed adequate ADC values for Nile tilapia.…”

Intestinal morphology and body development of Rhamdia quelen (gray-pink) and Astyanax altiparanae (gray-pink)

“…De hábito alimentar onívoro tendendo a carnívoro (Rodrigues et al, 2012;Fracalossi & Cyrino, 2013) apresentando o trato digestório gastrointestinal simples, e ausência de cecos pilóricos ou moela (Baldisserotto et al, 2014).…”