Effect of dietary phosphorus on the growth and body components of juvenile Synechogobius hasta

Abstract

The effect of dietary phosphorus on the growth and body components of juvenile Synechogobius hasta was determined. Different percentages of dietary phosphorus (0.63, 0.77, 0.93, 1.06, 1.22 and 1.36) were tested by feeding the fish (body weight, 15.81 g ± 0.32 g; 20 individuals each group; 3 groups each percentage) at a surplus of 5%-10% above satiation for 35 d. Dietary phosphorus did not significantly affect the specific growth rate, feed intake, feed conversion ratio and protein efficiency rate. Nitrogen retention was found to be the highest in fish fed the diet containing 1.06% of phosphorus; however, this was not significantly different from other diets. Fish fed the diet containing 0.93% of phosphorus showed the highest phosphorus retention; similar phosphorus retention rates were found in fish fed the diets containing 0.77% and 1.06% of phosphorus. Fish fed the diet containing the highest percentage of dietary phosphorus were found to contain the least whole body lipid, lower than fish fed other diets (P<0.05). The protein content increased from 18.59% to 19.55% (although not significant) with the decrease of body lipid content (P>0.05). The contents of the whole body ash, whole body phosphorus and vertebrae phosphorus increased with dietary phosphorus percentage up to 1.06 (P<0.05), reaching a plateau after that. Dietary phosphorus did not significantly influence the muscle components (protein, lipid and moisture). Condition factor and hepatosomatic index were the highest in fish fed the diet containing 0.63% of dietary phosphorus; however, this was not significantly different from those of other diets. The second-order polynomial regression of phosphorus retention against dietary phosphorus identified a breakpoint at 0.88% of dietary phosphorus. However, the dietary requirement of phosphorus for maintaining maximum phosphorus storage determined by broken-line analysis of the contents of whole body phosphorus, and ash and vertebrae phosphorus was 1.06% of the diet.

Studies on dietary phosphorus requirement of juvenile Siberian sturgeon Acipenser baerii

“…The whole body ash and phosphorus have been commonly used as indicator of dietary phosphorus status in fish nutrition studies (Skonberg et al., 1997) and frequently used for determining minimum phosphorus requirements (Brown et al., 1993; Ketola and Richmond, 1994; Mai et al., 2006). A positive correlation was observed between dietary phosphorus and ash, calcium and phosphorus concentration of whole fish, scutae and vertebrae in our study, which is consistent with other reports (Luo et al., 2009). The requirement of dietary phosphorus of 1.04 and 0.87% based on the phosphorus content of scutae and whole fish was higher than 0.50% based on the WGR, previous studies showed that requirement estimates based on phosphorus accumulation in the body tissue tend to be higher than those based on growth rate (Brown et al., 1993; Ketola and Richmond, 1994; Vielma et al., 2002; Mai et al., 2006).…”

Dietary total phosphorus requirement of juvenile yellow catfish Pelteobagrus fulvidraco

“…These findings coincided with the results reported by Nordrum et al (1997), Satoh et al (2003) and Luo et al (2009). Rodehutscord (1996) Whole body ash content (%) Y = 1.59 + 5.11 X -3.01 X 2 R 2 = 0.77 0.85% increase of phosphorus intake.…”

“…In contrast, phosphorus deficiency leads to reduced whole body phosphorous concentration in other studies Baeverfjord et al 1998;Luo et al 2009). Whole body ash content increased with increasing dietary phosphorus from 0.43 to 0.90% and then declined with further increasing dietary phosphorus level.…”

“…Second-order regression analysis of whole body ash content indicated the optimal dietary phosphorus requirement for the best bone mineralization was 0.85%, similar to the value determined with SGR data. In several studies, the whole body ash level had been commonly used as indicators of dietary phosphorus status in fish nutrition studies (Hardy et al 1991;Skonberg et al 1997) and frequently used as a basis for determining minimum phosphorus requirements (Brown et al 1993;Mai et al 2006;Luo et al 2009). In the present study, a positive correlation between vertebrae phosphorus and dietary phosphorus had been observed, in agreement with many researchers (Brown et al 1993;Baeverfjord et al 1998;Chavez-Sanchez et al 2000;Luo et al 2009).…”

“…In several studies, the whole body ash level had been commonly used as indicators of dietary phosphorus status in fish nutrition studies (Hardy et al 1991;Skonberg et al 1997) and frequently used as a basis for determining minimum phosphorus requirements (Brown et al 1993;Mai et al 2006;Luo et al 2009). In the present study, a positive correlation between vertebrae phosphorus and dietary phosphorus had been observed, in agreement with many researchers (Brown et al 1993;Baeverfjord et al 1998;Chavez-Sanchez et al 2000;Luo et al 2009). Based on broken-line analysis of vertebrae phosphorus content against dietary phosphorus levels, the minimum requirement of dietary total phosphorus for the maximum storage of yellow catfish was 0.76% of the diet, which was lower than those determined with SGR and whole body ash content as the variables.…”