Impact of high dietary energy on obesity and oxidative stress in domestic pigeons

Abstract

Obesity is associated with increased risk of oxidative stress in humans and laboratory animals but information regarding obesity-induced oxidative stress in birds is lacking. Therefore, this study aimed to investigate the influence of high-energy diets (HED) on obesity and oxidative stress in domestic pigeons. Forty-five adult clinically healthy-domestic male pigeons were randomly assigned to three equal dietary groups including low (2,850 kcal/kg), medium (3,150 kcal/kg) and high (3,450 kcal/kg) energy diets (named low energy diet, medium-energy diet and HED, respectively). All birds received formulated diets for 60 consecutive days. Several parameters such as feed intake, body weight (BW), average weight gain (AWG) and total weight gain were determined. Serum concentrations of triglyceride (TG), total cholesterol (TC), high-, low- and very-low-density lipoprotein cholesterols, alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) were evaluated at days 0, 30 and 60; and serum levels of total antioxidant capacity (T-AOC), malondialdehyde (MDA) and cortisol were also measured at day 60. On day 60, five pigeons from each group were randomly euthanized and some parameters such as weight and relative weight of liver, breast muscle, and abdominal fat were determined. Furthermore, hepatic total fat content was also evaluated. BW, AWG, total weight, and circulating TG, TC, ALT, AST, ALP, MDA and cortisol in HED were significantly higher than other groups. Serum T-AOC in HED was significantly lower than the other groups. In conclusion, this study showed that increasing dietary energy up to 3,450 kcal/kg in pigeons led to obesity and oxidative stress in them. Accordingly, it could be stated that HED and obesity induce oxidative stress in pigeon and controlling the dietary energy intake of pigeons is necessary to prevent oxidative stress in them.

Keywords: dietary energy; obesity; oxidative stress; pigeon.

FIGURE 1

Circulating levels of lipid profile and hepatic enzymes (mean ± SE) in pigeons fed by three different levels of dietary energy. ALT, alanine aminotransferase; ALP, alkaline phosphatase; AST, aspartate aminotransferase; HDL, high‐density lipoprotein cholesterols; HED, high‐energy diet; LDL, low‐density lipoprotein cholesterols; LED, low‐energy diet or control group; MED, medium‐energy diet; TC, total cholesterol; TG, triglyceride; VLDL, very‐low‐density lipoprotein cholesterols. ^a,b,cDifferent letters in the superscripts indicate significant differences (p <.05)

FIGURE 2

The levels of triglyceride and total cholesterol in liver tissue of pigeons fed by three different levels of dietary energy. HED, high‐energy diet; LED, low‐energy diet or control group; MED, medium‐energy diet. ^a,b,cDifferent letters in the superscripts indicate significant differences (p <.05)