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An 8‐week growth trial was conducted to investigate the effects of non‐genetically modified (nGM) soybean (Youchun 06‐1) and genetically modified (GM) soybean (Roundup Ready®) with and without a heat treatment on the growth and health of three Cyprinidae species with different feeding habits (grass carp Ctenopharyngodon idellus, gibel carp Carassius auratus gibelio, and black carp Mylopharyngodon piceus; body weight: 283.0 ± 2.0 g, 60.5 ± 0.7 g, and 261.4 ± 3.1 g). Five diets (FM, nGMS, hnGMS, GMS, and hGMS) were made with fishmeal and full‐fat soybean (Youchun 06‐1, heat‐treated Youchun 06‐1, Roundup Ready®, and heat‐treated Roundup Ready®). The FM diet contained fishmeal as the sole protein source. The experimental diets contained full‐fat soybean meal as 60% of dietary protein. Both temperature (60, 80, 100, and 120°C) and duration (1 and 2 hr) of heating influenced trypsin inhibitor activity (TIA) and protein solubility of nGM soybean and GM soybean. The TIA in GM soybean was higher than that in nGM soybean. After heating at 120°C for 2 hr, each amino acid of soybean treatment showed a slight decline. Neither source of soybean nor heat treatment affected the growth performance, feed utilization, chemical composition of the whole fish body and muscle, and lipase or amylase activity of the three Cyprinidae species (p > 0.05). Heat treatment of soybean meal slightly increased the plasma antioxidant capacity of the three fish and plasma cholecystokinin of black carp and grass carp. The unheated soybean treatment adversely affected the height and density of black carp intestinal villi, and all the soybean treatments caused disruption of the grass carp intestinal epithelium. [ABSTRACT FROM AUTHOR]

Abstract: A 57‐day growth experiment was conducted with juvenile gibel carp (13.48 ± 0.10 g) in a flow‐through system to study the effect of dietary phosphorus on growth performance, body composition, nutrition utilization, phosphorus loading and enzymes activities. Seven semipurifed diets were formulated to contain 0.07 (the basal), 2.27, 5.32, 8.10, 12.06, 15.24 and 19.48 g available phosphorus/kg diet. The results showed that specific growth rate, body length and feed efficiency significantly increased in the fish fed diets containing 0.07 to 15.24 g available P/kg diet (p < .05). Ash and P content increased in fish fed diets containing 0.07–12.06 P g/kg (p < .05) and then levelled off, while moisture, crude protein and lipid had no significant difference (p > .05). The protein retention efficiency increased in the fish fed with diets 0.07–5.32 g/kg P (p < .05) and then reached a plateau. The P content in faeces was higher in fish fed diets containing 15.24 and 19.48 g available P/kg. Total P concentration in tank water increased in fish fed 0.07–12.06 g available P per kg diet (p < .05). The plasma P was higher in the fish fed with 15.24 g available P/kg diet (p < .05), triglycerides was lower in the fish fed diet containing 15.24 and 19.48 g available P/kg (p < .05), no significant differences were observed in plasma Ca, plasma glucose and calcitonin (p > .05). Based on SGR, whole body P content and FE, dietary available P requirement for juvenile gibel carp were 13.37, 13.97 g/kg and 15.06 respectively. [ABSTRACT FROM AUTHOR]

Abstract: An 88‐day experiment was conducted in a flowing system to evaluate the effects of dietary vitamin C on growth, body composition, antioxidant and gonad development of on‐growing gibel carp. Triplicate tanks of gibel carp (77.2 ± 0.1 g) were randomly fed with one of seven experimental diets containing l‐ascorbic acid of 0, 101.1, 188.5, 313.1, 444.1, 582.1 and 747.0 mg/kg, respectively. The results showed that specific growth rate (SGR) and feed efficiency (FE) of fish were not affected by dietary l‐ascorbic acid. Dietary l‐ascorbic acid of 444.1 mg/kg diet led to low levels (p < .05) of gonadosomatic index (GSI) and hypothalamic gonadotropin‐releasing hormone (GnRH) in on‐growing fish, as well as the early ovarian stages (Developing stages) compared with fish (Maturing stages) from the other groups. Dietary l‐ascorbic acid supplementation increased (p < .05) the dorsal muscle collagen content, but did not affect the protein or lipid content of dorsal muscle in gibel carp. Plasma total antioxidant capacity (T‐AOC) and superoxide dismutase (SOD) activity increased (p < .05) and then remained unchanged with the increase in dietary l‐ascorbic acid levels. Dietary l‐ascorbic acid of 101.1 mg/kg diet improved (p < .05) plasma lysozyme activity of the fish. Broken‐line regression indicated that dietary l‐ascorbic acid requirement of 77 g gibel carp was 223.3 or 225.0 mg/kg diet based on plasma T‐AOC or SOD activity, which was a little higher than that based on plasma l‐ascorbic acid concentration (193.2 mg/kg). [ABSTRACT FROM AUTHOR]

A 12-week growth trial was conducted in a flow-through system to determine dietary selenium (Se) requirement for on-growing gibel carp (initial body weight: 76.2 ± 0.05 g, mean ± SEM). Selenomethionine was supplemented to the basal diet to formulate seven semi-purified diets containing 0.26, 0.58, 0.72, 1.14, 1.34, 1.73 and 2.09 mg Se kg−1 diet. The results showed that plasma superoxide dismutase (SOD) activity significantly increased when fish were fed with 0.58 mg Se kg−1 diet ( P < 0.05) and then decreased at 2.09 mg Se kg−1 diet ( P < 0.05). Plasma T-AOC activity was higher in fish fed with 0.72 mg Se kg−1 diet ( P < 0.05) and plasma malondialdehyde (MDA) was higher in fish fed with 0.26 mg Se kg−1 diet ( P < 0.05). When fish were fed 1.14 mg Se kg−1 diet, hepatic GSH-Px, T-AOC, GSH and CAT activities were significantly higher than those fed with 0.26 mg Se kg−1 diet ( P < 0.05). Hepatic superoxide dismutase (SOD) activity was higher at 1.34 mg Se kg−1 diet ( P < 0.05). Fish liver Se concentrations were significantly higher when fed with 0.72 mg Se kg−1 diet ( P < 0.05) and then kept constant when Se ≥ 0.72 mg kg−1 ( P > 0.05). Whole-body and muscle Se concentrations were higher when fed with 1.34 mg Se kg−1 diet ( P < 0.05) and kept a plateau when Se ≥ 1.34 mg kg−1 ( P > 0.05). In conclusion, based on broken-line regression of hepatic Se concentrations, hepatic SOD activity and hepatic T-AOC activity, dietary Se requirements for on-growing gibel carp was 0.73 mg kg−1, 1.12 mg kg−1 and 1.19 mg kg−1 diet respectively. [ABSTRACT FROM AUTHOR]

An 84-day growth trial was designed to investigate effects of dietary replacements fish oil with pork lard ( PL) or rapeseed oil ( RO) on growth and quality of gibel carp ( Carassius auratus gibelio var. CAS III) (initial body weight: 158.2 ± 0.2 g), and responses of the fish refed fish oil ( FO) diet. Three isonitrogenous (crude protein: 30%) and isolipid (crude lipid: 10%) diets were formulated containing 7.73% FO, PL or RO. Five experimental treatments including FO group ( FO), PL group ( PL), RO group ( RO), group fed PL for 42 days and refed FO for 42 days ( PL+ rFO), RO and refed FO group ( RO+ rFO) was tested. At the end of first 42 days, the fish fed PL and RO had higher mortality than that of the control ( P > 0.05). At the end of whole experiment, fish fed PL and RO showed higher plasma cortisol than FO fish ( P < 0.05). RO+ rFO fish showed higher lysozyme activity than RO fish ( P < 0.05). Fish growth and feed utilization, composition of whole body and muscle, free amino acids, texture, off-flavour substances or sensory attributes were not affected by dietary treatments ( P > 0.05). PL and RO diet decreased muscle EPA, DHA and n-3/n-6 ratio ( P < 0.05), while FO-refeeding had recovery effect. It can be concluded that the replacement of FO by PL and RO does not affect the growth, feed utilization or fish tasting quality in gibel carp. Fish muscle fatty acids modified by dietary PL and RO can be recovered by refeeding with FO diet. [ABSTRACT FROM AUTHOR]

A 8 week growth trial of three feeding frequencies (2, 4 and 6 meals day-1) and three dietary protein levels (30%, 34% and 38%) was conducted to investigate the influence of feeding frequency and dietary protein level on growth, feed utilization, serum free essential amino acids (EAA) dynamics and nitrogen (N), phosphorus (P), carbon (C) retention in juvenile allogynogenetic gibel carp (Carassius auratus gibelio) 'CAS III'. The results showed that feeding frequency and dietary protein level increased feed intake (FI), specific growth rate (SGR) and feed efficiency (FE). SGR increased significantly with the increase in feeding frequency and dietary protein level. But, the increase in dietary protein level from 30% to 38% in group 6 meals day-1 did not result in better growth. Compared with the group of 4 meals day-1 × 38%, the fish fed the diet containing 30% crude protein at 6 meals day-1 obtained similar SGR but showed lower FIp (protein intake). Compared with 2 meals day-1, NREs (nitrogen retention efficiency) of 4 and 6 meals day-1 were relatively higher. PRE (phosphorus retention efficiency) and CRE (carbon retention efficiency) increased significantly with feeding frequency while TNW (total nitrogen waste output), TPW (total phosphorus waste output) and TCW (total carbon waste output) decreased significantly. Feeding frequency and dietary protein level increased trypsin activity. Serum free EAA concentrations varied more synchronously at 6 meals day-1 than 2 meals day-1. It could be concluded that increasing feeding frequency could improve growth by increasing feed intake and feed efficiency for juvenile gibel carp. The increase in feeding frequency showed proteinsparing effect. [ABSTRACT FROM AUTHOR]

Two 8-week feeding trials were conducted to evaluate dietary carbohydrate utilization by omnivorous gibel carp (Carassius auratus gibelio) (2.4 ± 0.1 g) and herbivorous grass carp (Ctenopharyngodon idellus) (6.5 ± 0.1 g). Five isonitrogenous (370 g kg -1) and isolipid (70 g kg -1) diets were formulated with increasing corn starch levels (60, 140, 220, 300 and 380 g kg -1). Results showed that specific growth rate (SGR), feed efficiency (FE) and protein retention efficiency (PRE) of gibel carp significantly increased from dietary starch of 60 to 300 g kg -1 and then decreased from 300 to 380 g kg -1, but those of grass carp showed no significant differences between treatments. Independent of dietary starch levels, grass carp gained significantly higher FE and PRE than gibel carp. Feeding rate (FR) of gibel carp was significantly higher than that of grass carp. In two fish species, high dietary starch (300 and 380 g kg -1) tended to obtain higher hepatosomatic index (HSI), serum triglyceride, hepatic lipid and body lipid contents. Serum glucose concentration of grass carp was not affected, while that of gibel carp fed the starch of 300 g kg -1 diet was significantly lower than those of the fish fed other four diets (60, 140, 220 and 380 g kg -1). Grass carp showed high tolerance to dietary starch while dietary corn starch should be no more than 300 g kg -1 for gibel carp. High starch contents may cause lipid accumulation in the liver and body. [ABSTRACT FROM AUTHOR]