Effect of dietary phosphorus levels on growth and body composition of crucian carp, Carassius auratusunder indoor and outdoor experiments

Abstract

Indoor and outdoor experiments were carried out simultaneously to evaluate the effects of dietary phosphorus levels on growth performance and body composition of crucian carp. Monocalcium was used to formulate extruded feed containing available phosphorus (AP) of 1.5 (D1), 4.7 (D2), 6.3 (D3) and 9.0 (D4) g kg À1 . Twelve 500-L recirculating tanks were assigned to four triplicate groups with each tank stocked with 15 juveniles (39.88 AE 0.14 g) for indoor experiment. Twelve polyethylene enclosures were assigned to four groups with each one stocked with 120 juveniles (44.08 AE 1.36 g). After 8 weeks of feeding, survival ranged from 96% to 100%. Weight gain, special growth rate, protein efficiency ratio and feed conversion rate did not show significant differences among dietary treatments in both experiments. Fish cultured in the enclosures grew better, although D1 and D2 treatments did not reach significant level. Crude protein and phosphorus content of the fish were not significantly affected by dietary phosphorus level. Moisture, crude lipid, crude ash and vertebrae phosphorus were significantly affected by different phosphorus levels. Based on vertebrae phosphorus, crucian carp cultured in the tanks and in the enclosures showed phosphorus deficiency under 4.7 g kg À1 and 6.3 g kg À1 AP, respectively.

Dietary available phosphorus requirement of crucian carp, Carassius auratus

“…A comparison of the SGR in tank experiments carried out by Chen et al. () (1.19%–1.23%/day) with that in the present research (0.94%–1.20%/day) found that although the feeding rate was much lower in the present experiment, the fish had an SGR that is equivalent to that observed in the experiment of Chen et al. () when sufficient dietary P was provided.…”

“…() (1.19%–1.23%/day) with that in the present research (0.94%–1.20%/day) found that although the feeding rate was much lower in the present experiment, the fish had an SGR that is equivalent to that observed in the experiment of Chen et al. () when sufficient dietary P was provided. The contradictory results of these two experiments revealed that the effect of dietary P level on growth was highly related to the feeding rate.…”

“…The different responses probably resulted from a much higher feeding rate in those experiments (3% body weight, two meals a day, which took the crucian carp approximately 1 hr to consume one meal) that might compensate for the low P supply treatment groups. A comparison of the SGR in tank experiments carried out by Chen et al (2017) (1.19%-1.23%/day) with that in the present research (0.94%-1.20%/day) found that although the feeding rate was much lower in the present experiment, the fish had an SGR that is equivalent to that observed in the experiment of Chen et al (2017) when sufficient dietary P was provided. The contradictory results of these two experiments revealed that the effect of dietary P level on growth was highly related to the feeding rate.…”

“…The difference was probably caused by many factors, such as fish species and size, forms of P (e.g., solubility of P), culture systems and different experimental designs Prabhu et al, 2013;Zhang et al, 2006). In a previous research carried out by Chen et al (2017), the growth of crucian carp (40-44 g) was not affected by four graded levels of dietary P in both recirculating tanks and outdoor pond enclosures. The different responses probably resulted from a much higher feeding rate in those experiments (3% body weight, two meals a day, which took the crucian carp approximately 1 hr to consume one meal) that might compensate for the low P supply treatment groups.…”

“…Crucian carp ( Carassius auratus ) is one of the most widely cultured fish in China (Chiu et al., ). Although many research studies on the P requirement of various kinds of cultured fish have been conducted (Deschamps, Poirier Stewart, Demanche, & Vandenberg, ; Nwanna, Kühlwein, & Schwarz, ; Prabhu, Schrama, & Kaushik, ; Shen et al., ; Wang et al., ; Xie et al., ), there are very few studies on the optimal available P (AP) requirement for this fish (Chen, Sun, Kong, Tang, & Gan, ). This study was aimed to evaluate the growth performance, body composition and blood chemistry of crucian carp under different dietary P levels in order to determine the dietary AP requirement of the fish.…”