Despite the well‐documented herbivorous food habits, commercial feeds for production of Oreochromis niloticus usually contain between 7% and 15% animal protein. However, animal protein feedstuffs are expensive, hence the need to search for cost‐effective alternatives in plant‐protein sources. Such alternatives are probably more effective in semi‐intensive systems where natural pond food forms part of the diet. This study evaluated the performance of O. niloticus after feeding diets in which fresh shrimp meal (SM) was gradually replaced by a mixture of plant‐protein sources in fertilized ponds. Three isonitronegenous (24% crude protein) diets containing 12 (control), 6% and 0% SM were fed to three groups of O. niloticus in four replicates per group for 250 days. Fish were fed daily at 2% body weight and sampled monthly to monitor growth and make feed adjustments. Growth, yields, survival and feed conversion ratio were not significantly different (P>0.05) among treatments. Growth of males was double that of females, while the sex ratio was skewed towards females. Although complete substitution of SM by plant protein did not affect the growth of tilapia, production cost was reduced by 36%. In conclusion, animal protein is not required in diets for production of O. niloticus in fertilized ponds.
The e¡ects of open-water and caged ¢sh density on growth, feed utilization, water quality and pro¢tability were investigated to assess the feasibility of a small-scale rotational system for production of Oreochromis niloticus (L.) in fertilized ponds. Hand-sexed male ¢ngerlings averaging 18.6 and 29.9 g were stocked in open water and cages, respectively in four treatments with open-pond:caged tilapia ratios of 300:0 (control), 150:150 (L), 300:150 (H1) and 300:300 (H2). The ponds in L and H1 contained one cage, two cages in H2, and the control ponds had no cages. Each cage contained 150 ¢sh, which were fed daily at 1.5% body weight for 125 days. All ¢sh in the open water except the control ¢sh were not fed. Growth of open water tilapia was signi¢cantly (Po0.05) higher in L than in control. Feed utilization, dawn DO and economic returns were signi¢cantly better (Po0.05) in caged than control ponds. Growth of tilapia in L was signi¢cantly lower (Po0.05) in cages than in open water. Fingerling production was signi¢cantly lower (Po0.05) in L than in other treatments. In conclusion, cage-cum-open-pond integrated treatment (L) was optimal for O. niloticus production in fertilized ponds. However, the system could not rotate and needed further ¢ne-tuning to rotate.
This study compared the cost-effectiveness of a back exercise programme for different levels of back pain with standard treatment. The back exercise programme resulted in a reduction in back pain after 2 years compared with standard treatment. Moreover, the exercise programme resulted in reduced medical costs. The back exercise programme was found to be therapeutically effective and cost-efficient. The therapeutic and economic effects of the programme increased with severity of back pain. Objective: To compare the cost-effectiveness of a multimodal back exercise programme for non-specific back pain with that of standard treatment. Medical costs were measured in euros (EUR) and effectiveness was measured using Graded Chronic Pain Status (GCPS). Design: A controlled multicentre study (39 sites) with a 6-month intervention phase and follow-up at 6, 12 and 18 months. Subjects: The study included 1,829 participants in an intervention group and 495 individuals in a control group. Methods: The multimodal back exercise programme comprises 36 exercise sessions for optimizing the spine stabilizing muscles and everyday motor functions. The patients were given a home training programme at the end of the intervention programme. Results: The back exercise programme resulted in a significant reduction, of 0.4, in back pain grade on the GCPS after 2 years, compared with standard treat ment, and reduced medical costs by 763 EUR. The exercise programme was therapeutically effective for GCPS back pain grades 1-4 and produced cost savings in the case of grade 4 GCPS. Conclusion: The multimodal back exercise programme was therapeutically effective for back pain (grades 1-2) and pain-related functional impairment (grades 3-4). It resulted in reduced costs for chronic back pain causing high pain-induced functional impairment (grade 4). The therapeutic and economic effects of the programme increase with the grade of back pain.
The effects of pond fertilization and feeding rate on growth, economic returns and water quality were investigated to develop a low‐cost cage‐cum‐pond integrated system for production of Oreochromis niloticus (L.). Hand‐sexed male fingerlings averaging 19±0.39 and 32±0.69 g were stocked in cages and open ponds at 150 fish cage−1 and 2 fish m−2 respectively. Fish were cultured for 114 days in five triplicate treatments. Cages were installed into ponds and caged fish were fed a 24% protein diet at 3% (T1) and 6% (T2) body weight day−1 (BWD) without pond fertilization, and 6% BWD with pond fertilization (T3). The open water in the fourth treatment (T4) was not stocked but contained caged fish, which were fed 6% BWD for the first 57 days followed by 3% BWD for the remaining period. Ponds in the control (T5) had no cages and were neither fertilized nor open‐pond fish fed. Feeding rate and pond fertilization significantly (P<0.05) affected fish growth, profitability and water quality among treatments. Fish growth, feed utilization, fish yield, water quality and profits were significantly (P<0.05) better in T3 than the other treatments. It was concluded that fish production and economic returns were optimized at 6% BWD in fertilized ponds.
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