Carbohydrate tolerance in the fruit-eating fish Piaractus mesopotamicus (Holmberg, 1887)

Abstract

Some fish species have a limited ability to metabolize dietary carbohydrates. An important tool for understanding carbohydrate metabolism is the application of the glucose tolerance test, which can be performed orally or intraperitoneally. To evaluate carbohydrate tolerance in the fruit-eating fish pacu, two experiments were performed, one with oral administration by gavage of three carbohydrate types (glucose, fructose and starch, 2.0 g/kg body weight (BW)) and the other with intraperitoneal injection (IP) of glucose (500 mg/kg BW). Oral glucose resulted in an increase in plasma glucose 2 hr later with the peak at 4 hr (8.30 mmol/L), and return to baseline between 6 and 12 hr; starch administration promoted a peak after 4 hr (7.70 mmol/L), returning to the baseline at 6 hr. The administration of fructose promoted a moderate peak after 2 hr (5.71 mmol/L), and return to baseline for the time points that followed. Elevated serum cholesterol levels were observed 2 and 24 hr after administration of glucose and starch. Hepatic glycogen levels increased within 24 hr, regardless of the type of carbohydrate administered. IP glucose load resulted in a peak of plasma glucose 3 hr post injection (6.91 mmol/L), returning to baseline 6 hr later. There was a reduction in the concentration of triglycerides at 24 hr. The results demonstrate that pacu metabolize both oral (glucose or starch) and intraperitoneal (glucose) carbohydrate loads after 6 hr, suggesting good ability to deal with dietary carbohydrates. K E Y W O R D S fish, glucose, hyperglycaemia, metabolism, omnivorous, pacu wileyonlinelibrary.com/journal/are Aquaculture Research. 2018;49:1182-1188.

Growth performance and metabolic responses to dietary protein/carbohydrate ratios in pacu ( Piaractus mesopotamicus ) juveniles

“…Pacu is a frugivorous fish, showing a high capacity to deal with a glucose load administered both orally and intraperitoneally (Takahashi et al., 2018), and a high ability to utilize plant‐derived ingredients (Abimorad, Squassoni, & Carneiro, 2008). Thus, the use of high dietary carbohydrates levels as an energy source seems a practicable alternative to reduce aquafeeds costs for this species.…”

“…Glucose tolerance tests revealed that pacu metabolizes an oral starch (2.0 g/kg body weight) load relatively fast, with plasma glucose levels peaking at 4 hr and returning to the basal level within 6 hr after starch administration (Takahashi et al., 2018). In the present study, plasma glucose was only measured in 24‐hr unfed fish, but even after such a long time, feeding fish with dietary starch at 400 g/kg led to higher plasma glucose levels than in fish fed diets including 350 g/kg starch, indicating that high dietary starch levels cause prolonged postprandial hyperglycaemia in pacu.…”

“…However, the capability to utilize dietary carbohydrates varies greatly among fish species, depending on factors such as fish species, feeding habits, genotype; carbohydrate botanical origin, molecular complexity, physical status, dietary inclusion levels; and environmental parameters such as temperature, salinity, photoperiod (Enes, Panserat, Kaushik, & Oliva‐Teles, 2011; Kamalam, Medale, & Panserat, 2017). Overall, omnivorous and herbivorous species are known to use dietary carbohydrates as an energy source more efficiently than carnivorous species (Enes, Panserat, Kaushik, & Oliva‐Teles, 2009; Polakof, Panserat, Soengas, & Moon, 2012; Takahashi, Ha, Pereira, Biller‐Takahashi, & Urbinati, 2018).…”

“…mesopotamicus ) is a widely cultivated fish in Argentina and Brazil, being one of the most important economically farmed fish species in Brazil (FAO, 2018; Valladão, Gallani, & Pilarski, 2018). It has omnivorous feeding habits, but until now few studies have focused on the use of dietary carbohydrates in this species (Abimorad & Carneiro, 2007; Abimorad, Carneiro, & Urbinati, 2007; Honorato et al., 2016; Honorato, Almeida, Nunes, Carneiro, & Moraes, 2010; Takahashi et al., 2018). Abimorad et al.…”

Desempenho Zootécnico E Financeiro De Bovinos Confinados Com Acesso a Diferentes Áreas De Sombreamento E a Pleno Sol / Zootecnical and Financial Development of Confined Bovines With Access to Different Areas of Shading and Exposed to the Sun

“…O desempenho produtivo dos animais pode ser influenciado por condições climáticas adversas, resultando em perdas de produção e produtividade (FURTADO et al, 2012). Em ambientes de termoneutralidade, a energia metabolizada pode ser destinada quase que em sua totalidade à produção, não sendo necessária a destinação de energia para uso dos mecanismos de termorregulação (TAKAHASHI & BILLER, 2009). O fornecimento de sombra durante o período de confinamento traz benefícios ao desempenho animal, e a implantação de instalações de sombrite como fonte artificial de sombreamento demonstrou influência positiva no desempenho de bovinos confinados.…”