Age factor and proximate compositions of the muscle of Heterobranchus Bidorsalis exposed to graded concentrations of bonny-light crude oil

Abstract

Variationsin the proximate compositions of three age groups of Heterobranchus bidorsalis exposed to graded concentrations of Bonny-light crude oil (BLCO) were investigated in the laboratory. The sh were exposed to 1.00, 2.00, 4.00 and 8.00 ml L-1 concentrations of BLCO for 4 days (toxicity) and 42 days (recovery) periods. Signiicant decreases (P < 0.05) in the crude protein (CP), ether extract (EE), ash (AS) and dry matter (DM) contents of the juvenle (JV), the yearling (YRL) and theadult (AD) fish were BLCO-concentration dependent. Lower CP values in the adult fish than in the juveniles or the yearlings implies that the crude oil compounds might have depeted the quantity oprotein faster in the adults than in the juveniles or the yearlings. Signiicant decreases (P < 005) in the EE content of the fish muscle could be attributed to the harmful effects of petroleum-relatedaromatic compound (ACs) on animals. These ACs might have caused decreases in the muscle triglycerides of the total lipid (EE) content of thethree age groups of the fish. Significant increases (P < 0.05) in the nitrogen free extract (NFE) of the fish muscle might have been due to the high energy demand imposed on the fish as a positive survival value under the condition of crude oil stress.

Keywords: Heterobranchus bidorsalis, Age groups, Proximate composition, Bonny-light crude oil, Toxicity