Ontogeny and kinetics of carnitine palmitoyltransferase I in hepatopancreas and skeletal muscle of grass carp (Ctenopharyngodon idella)

Abstract

The ontogeny and kinetics of carnitine palmitoyltransferase I (CPT I) were investigated in hepatopancreas and muscle throughout four developmental stages (newly hatched larvae, 1-month-old juvenile, 3-month-old, and 6-month-old, respectively) of grass carp Ctenopharyngodon idella. In hepatopancreas, the maximal velocity (Vmax) significantly increased from hatching to 1-month-old grass carp and then gradually declined at 6-month-old grass carp. In muscle, CPT I activity was the highest at 1-month-old grass carp, nearly twofold higher than that at hatching (P < 0.05). The Michaelis constant (Km) value was also the highest for 1-month-old in both tested tissues. Carnitine concentrations (FC, AC and TC) were the lowest for 3-month-old grass carp and remained relatively constant in both tissues from fish under the other developmental stages. The FC concentration in hepatopancreas and muscle at four developmental stages were less than the respective Km, indicating that grass carp required supplemental carnitine in their food to ensure that CPT I activity was not constrained by carnitine availability.

Identification and Characterization of Carnitine Palmitoyltransferase 1 (cpt 1) Genes in Nile Tilapia, Oreochromis niloticus

“…The mRNA expression level of cpt 1α1a was the highest in the heart with, no statistically significant differences between the intestine, muscle, brain, kidney, and testis ( P < 0.05) (Figure 2). Similarly, the highest cpt 1α1a mRNA expressions were determined in the heart of javelin goby, 31 sea bream 39 and grass carp 40 (Table 3). Sister cpt 1 C duplicates ( cpt 1α2a and cpt 1α2b ) exhibited divergent transcriptional regulation in the intestine, muscle, brain, eye, adipose, heart, spleen, ovary, and testis, suggesting that tsWGD event in Nile tilapia genome following a duplication event in ancestor genome resulted in the divergence of cpt 1 C isoforms 36 and these two isoforms most likely are retained in the Nile tilapia genome because of sub- or neo-functionalization.…”