Broken-line Analysis (broken-line + analysis)

Distribution by Scientific Domains


Selected Abstracts


Phosphorus requirement of common carp (Cyprinus carpio L) based on growth and mineralization

AQUACULTURE RESEARCH, Issue 3 2010
L C Nwanna
Abstract The effect of diets supplemented with varied levels of inorganic phosphorus (P) (NaH2PO4) on the growth, body composition, nutrient digestibility and mineralization in common carp (Cyprinus carpio L) was evaluated to determine the optimum P requirements. The six diets used were DPO, as the basal diet with a total P content of 1.30 g kg,1, and DP1, DP2, DP3, DP4 and DP5, which contained 4.10, 6.70, 11.6, 14.9 and 23.4 g P kg,1 respectively. Weight gain, SGR, apparent digestibility coefficient of organic matter and P, whole body ash, P, Ca and Mg increased significantly with increasing dietary P levels while dry matter (DM), fat and Zn content decreased. Feed conversion ratio was the poorest (P<0.05) in fish fed DPO, suggesting P deficiency. The apparent digestibility coefficient of P was 18% in the DPO-fed group, which increased from 69% in DP1 to 92% in DP5 after P supplementation, revealing lower digestibility of the native P than that in NaH2PO4. Broken-line analyses based on weight gain, P content of fish bones and whole body against total dietary and digestible P (data in brackets) contents showed the optimum P requirement for the growth of common carp to be 6.87 (5.55) g kg,1 DM, and the requirement for optimum mineralization in bones and whole body to be 9.10 (7.62) and 14.7 (13.2) g kg,1. [source]


Effects of dietary phosphorus level on non-faecal phosphorus excretion from yellowtail (Seriola quinqueradiata Temminck & Schlegel) fed purified and practical diets

AQUACULTURE RESEARCH, Issue 2 2009
Pallab Kumer Sarker
Abstract Non-faecal phosphorus (P) was determined for large yellowtail to estimate a minimum available P requirement (Experiment 1) and to justify inorganic P supplementation in a fish meal-based diet (Experiment 2). In Experiment 1, purified diets with incremental P concentrations were fed to yellowtail (mean weight 917 g) at a feeding rate of 1.5% of body weight. The peaks of non-faecal P excretion appeared 5,6 h after feeding in fish fed more than 4.5 g available P kg,1 dry diet. Broken-line analysis indicated that the minimum available P requirement was 4.4 g kg,1 dry diet. In Experiment 2, a purified diet (PR) containing 6.5 g available P kg,1 and a fish meal-based diet with (F1) and without (F0) additional phosphorus were fed to yellowtail (mean weight 1.1 kg) at 1.5% (PR) and 2% (F0 and F1) feeding rates respectively. There was no significant difference in P excretion between fish fed the F0 (5.5 g soluble P kg,1 dry diet) and the PR diet. However, significantly higher (34.5%) amounts of non-faecal P excretions (7.4 g soluble P kg,1 dry diet) were found in fish fed F1 compared with the F0 diet. This suggested that there was an excess of dietary P in the F1 diet and that supplementation is not needed in fish meal-based diets for large yellowtail. [source]


Effect of dietary pantothenic acid supplement on growth, body composition and intestinal enzyme activities of juvenile Jian carp (Cyprinus carpio var. Jian)

AQUACULTURE NUTRITION, Issue 5 2009
Z.-P. WEN
Abstract A 9-week feeding trial was carried out with juvenile Jian carp to study the effect of dietary pantothenic acid (PA) on growth, body composition and intestinal enzyme activities. Semi-purified diets with seven levels (4.0, 15.5, 25.6, 36.1, 45.9, 56.1 and 65.9 mg PA kg,1) of supplemental calcium d -pantothenate were fed to Jian carp (13.0 ± 0.0 g). PA improved specific growth rate (SGR), protein productive value (PPV), protein efficiency ratio (PER) and lipid production value (LPV) (P < 0.05). Fish fed the control diet had significantly lower feed efficiency (FE) than that in any other group (P < 0.05). Body protein content increased with increasing PA levels (P < 0.05), but moisture, lipid and ash of fish carcasses were negatively related to the graded PA levels (P < 0.05). Intestine protein content (IPC), hepatopancreas protein content (HPC) and activity of ,-amylase, lipase, trypsin, Na+,K+ -ATPase, alkaline phosphatase (AKP) and gamma-glutamyl transpeptidase (,-GT) were all positively affected by the dietary PA levels (P < 0.05), while intestine index (ISI) and hepatopancreas index (HSI) decreased with the increment of supplemental levels of PA (P < 0.05). These results suggested that PA could enhance fish growth and intestinal enzyme activities. The dietary PA requirement of juvenile Jian carp, Cyprinus carpio var. Jian (13.0,73.0 g), for optimal growth estimated by the broken-line analysis was 23.0 mg PA kg,1 diet. [source]


Evaluation of zinc supplementation in European sea bass (Dicentrarchus labrax) juvenile diets

AQUACULTURE RESEARCH, Issue 9 2010
Eleni Fountoulaki
Abstract This study aimed to investigate the effect of increased zinc dietary levels on the growth performance, feed utilization, immune status and induced wound healing in European sea bass (Dicentrarchus labrax). Fish weighing 10 g were fed five diets containing organic zinc at 30, 70, 110 and 150 mg kg,1 diet and one inorganic zinc source (zinc oxide) at 150 mg kg,1 diet for a period of 12 weeks. No significant (P>0.05) differences were found in the growth performance parameters (final weight, specific growth rate), immunological indices tested (respiratory burst activity in whole blood) and the wound-healing process. Zinc accumulation in the skin, vertebrae and liver increased significantly (P<0.01) with increased dietary zinc levels but not in muscle. The highest zinc concentrations were obtained in skin tissue, followed by vertebrae, liver and muscle tissue. Using the concentration of zinc in skin as a response criterion, broken-line analysis showed that the supplementation of 148 mg organic Zn kg,1 diet seemed to be the optimum dietary zinc supplementation level for sea bass juveniles. [source]