Indicators of genetic variation for feed conversion efficiency in black bream

Feed conversion efficiency (FCE) is a composite measure that combines feed intake with growth rate to estimate the effectiveness by which feed is converted to saleable meat product, and is a major determinant of production system efficiency. We measured the relationships between feed intake to apparent satiety and weight gain in replicate half‐sib families of black bream at four times over a 56‐day test period. After 42 days, we found significant additive genetic variance in both weight gain and feed intake, and a stabilization in family group variation in both traits. This indicates that 42 days is the minimum test period over which to measure genetic variation for FCE in black bream. There were high, positive phenotypic (and probably genetic) correlations between weight gain and feed intake after 42 days. We found no detectable genetic variation for either feed efficiency (weight gain/feed intake), or residual feed intake, which is a linear function that distinguishes between the amount of feed intake that is used for body maintenance and that used for growth. We argue that selection for improved FCE might be better achieved not by using a composite measure, but by using a weighted selection index that accounts for the genetic covariance among weight gain, feed intake and other key production traits.     

Evaluation of potential feed sources,and technical and economic considerations of small‐scale commercial striped catfish (Pangasius hypothalamus) pond farming systems in the Mekong Delta of Vietnam

A technical and socio‐economic survey was conducted in Dong Thap, Can Tho and An Giang, provinces of Vietnam in 2009. The results showed that most of the small scale farmers of striped catfish (Pangasius hypothalamus) carry out fish pond culture, developed and operated by self‐learned experience and from neighbours knowledge. The mean pond depth varied from 3.5 to 4.0 m, ranging from 2 to 6 m. Most of the fish farms have extremely high stocking density, with an average of about 40 fish m^?2, in some cases up to 70 fish per m². The average yields and net income of small‐scales pond farming is about 21–27 kg per m² crop^?1 and US$ 0.184–0.329 kg^?1 crop^?1 respectively. These figures are not significantly different compared with large‐scale pond farming. About 75%, 86% and 80% of fish farmers in Dong Thap, Can Tho and An Giang province, respectively, received positive net returns. Farm‐made feed is still playing an important role because of higher net profit compared with commercial pellet feeds. Rice bran and trash fish are the main feed ingredients for farm‐made feed formulations. Striped catfish farmers are now actively searching for locally produced plant protein sources as alternatives to marine trash fish or fish meal.     

Effect of drying on the viability of the probiotic bacterium Lactobacillus plantarum Lab9 (CPQBA 144‐09 DRM 03) impregnated in the feed for tilapia (Oreochromis sp.)

Drying experiments were conducted at different temperatures and air flux velocities to determine the proper drying conditions for reducing moisture in commercial fish feed impregnated with probiotic lactic acid bacteria and to assess the effect on bacteria viability over time. At temperatures of 45°C, the drying time was shorter, without the air flux velocity under study having a relevant influence. The drying conditions influenced the viability of the bacteria in the feed; the least loss of viability was obtained with a velocity of 0.8 m s^?1 and a temperature of 45°C during 15 min. Using these drying conditions, 5 kg of feed was dried and stored for a month at temperature of 26°C and relative humidity of 75%. The viability of the bacteria and the moisture of the feed were measured every 3 days during the storage period. Loss of viability followed first order kinetics, with a constant k of 0.112 days^?1. Thus, the viability of the bacteria in the feed is less than 10⁶ CFU g^?1 after 43 days.     

A review of the effects of ingredient composition and processing conditions on the physical qualities of extruded high‐energy fish feed as measured by prevailing methods

Feed comprises the biggest cost in intensive fish farming and the quality of feed is therefore important. A vast body of research has been carried out in order to investigate nutritional quality of alternative ingredients. Effects of ingredients on physical quality are seldom included in these investigations. Physical quality of feed varies with ingredient composition and processing condition and may interfere with feed intake, nutrient digestibility and therefore growth performance of the fish. In this review, physical quality of extruded, high energy feed, and how ingredient composition and processing conditions affect the quality will be addressed. Various pellet properties will be discussed and methods used to evaluate physical quality will be reviewed.     

福建省水产饲料业的崛起与学科进步

水产养殖业的迅速发展带动了水产饲料业的进步。福建省水产饲料业经过近30年的稳步发展,饲料研发能力、产品产量与质量等均有较大的提高。本文概述了福建省水产饲料业的崛起与学科建设,指出了福建省水产饲料学科建设的重点发展方向。     

比较3种饲料对牙鲆生长和消化率的影响

选取平均体重为(359±16)g/尾的健康牙鲆48尾,随机分成3组,每组2个重复。采用3种不同饲料进行投喂,比较牙鲆专用配合饲料对牙鲆生长速度、饲料效率及消化率的影响。经过42d的饲养,结果表明:自配饲料(A组)增重速度最快、饲料系数最低,尾相对增重率达到230.1%、饲料系数达到1.59。牙鲆每增重1.0kg所需饲料成本最低,与B组、C组相比分别节省了13.7%和18.9%。A组的干物质消化率为81.56%,比B组、C组分别高5.33%和9.39%。A组的蛋白质消化率为91.17%,比B组、C组分别高3.26%和7.51%。     

影响鱼用颗粒饵料系数因素的分析

水、种、饵是八字精养法的三大物质基础 ,而饵料更是集约化、规模化养殖的重中之重 ,饵料费用一般占养殖总成本的 5 0 %以上 ,因此 ,如何解决饵料问题是养殖生产的关键问题之一。本文从饵料的配方、加工工艺、投喂技术和水环境因子等方面对影响饵料系数的因素进行了分析。     

使用颗粒饵料养殖鲈鱼试验

本文报道了颗粒饵料养殖鲈鱼的效果。结果表明；使用颗粒产与使用鱼浆比较，鲈鱼增重率提高２．７０％，饵料系数降低２７．６％。     

不同开口饵料对江鳕仔鱼生长及存活率的影响

采用海水皱褶轮虫（Brachionus plicatilis）、淡水臂尾轮虫（Bruchionus sp.）（维持有小球藻（Chlorella sp.））、超微粒子饵料、水丝蚓（Tubifex sp.）肉糜、摇蚊幼虫（Chironomus sp.）肉糜五组不同饵料进行江鳕仔鱼开口饵料选择试验。经15 d培育,结果表明：淡水轮虫是江鳕仔鱼最佳开口饵料,生长速度最快,成活率最高（95.42%）。     

The effect of feed supply rate on growth of juvenile perch (Perca fluviatilis)

This study investigates the effect of the feed supply rate within a meal on growth of juvenile perch (Perca fluviatilis). Groups of PIT-tagged, feed-trained juvenile perch (12 g) were held in 100-L tanks at 18 °C, under a 24L:0D photoperiod and fed five meals per day in excess. Feed was applied at rates of 1.2 (Low), 4.2 (Medium) and 14.3 (High) pellets fish⁻¹ min⁻¹ during two periods, each of 50 days. Cumulative meal-time per day ranged from 10 to 225 min. Specific growth rates (SGR) in the two periods were positively correlated, indicating a consistent individual growth performance. There was growth dimorphism between the sexes. Females grew about 20% faster than males, resulting in final mean weights of ≈ 87 and 58 g respectively. Autopsy revealed differences in sex ratios between treatments and the effect of feeding rate was analysed according to sex. There was a tendency for fish fed at the lowest rate to have a higher SGR than fish in other treatments, both for females (L = 1.98 ± 0.0, M = 1.84 ± 0.08, H = 1.88 ± 0.19% bw day⁻¹) and males (L = 1.68 ± 0.01, M = 1.55 ± 0.16, H = 1.57 ± 0.02% bw day⁻¹). Fish fed at the lowest rate also tended to have the lowest feed conversion ratio (L = 0.88 ± 0.05, M = 1.02 ± 0.11, H = 1.04 ± 0.10) but the effects were not significant. These results suggest that juvenile perch can feed efficiently under a range of conditions.     

Effects of feeding frequency on growth,feed efficiency and body composition of juveniles Brazilian sardine,Sardinella brasiliensis (Steindacher 1879)

The Brazilian sardine is the most important fishery resource in Brazil. Their production has declined along the last 30 years due the overfishing, climatic and oceanographic phenomena. This study was carried out to determine the optimal feeding frequency for juvenile Brazilian sardine based on growth, feed efficiency, feed intake and body composition. Six feeding frequencies of one, two, three, four, five and six times a day were evaluated in triplicate tanks for 50 days. Fish with initial mean weight of 3.29 ± 0.56 g were fed daily to apparent satiation. The results showed that fish fed once daily had lower body weight gain, specific growth rate and condition factor (P < 0.05) compared with other treatments. The feed efficiency ratio in fish fed once daily was significantly higher (P < 0.05) than those fed two or more times a day. No significant differences were observed in the coefficient of variation in body weight (P > 0.05) among the treatments. Feed intake was directly proportional to the feeding frequency. Fish fed once daily showed lower hepatosomatic and mesenteric fat indices (P < 0.05) than the other treatments. Neither protein nor ash content of fish were significantly (P > 0.05) affected by feeding frequency. However, the lipid content increased with feeding frequency. The results suggest that the optimal feeding frequency for juvenile Brazilian sardine is at least twice daily.     

饲用酶制剂在水产动物中应用的最新研究进展

酶制剂作为一类安全、高效的绿色饲料添加剂,在畜禽类饲料中已得到广泛应用.酶制剂不仅可以在一定程度上缓解国内饲料资源的不足,还可以促进绿色养殖环境的发展.由于酶制剂受热敏性条件制约的原因,其在水产饲料中的应用率较低,但随着一些设备的应用,如多道真空后喷涂等,使液体酶制剂在水产饲料中的广泛应用成为可能.本研究就酶制剂在水产...     

Selection of marine species and meals for cephalopod feeding based on their essential mineral composition

A quantitative analysis of the essential mineral content (mg kg^?1 dry weight) was carried out in 31 samples, including molluscs, crustaceans, fish and meals in an attempt to identify those most suitable for formulating cephalopod diets. The mineral ratios (MR: content in the test sample/content in whole Octopus vulgaris) were used as index of nutritional quality. Both crustaceans and oysters presented an optimal profile that covered the macro‐ and microelements composition of O. vulgaris. These samples differed from the rest by their higher Ca, Mg, B, Cu and Zn contents based on a principal component analysis. Fish were deficient in macroelements, such as Na (MR: 70–420 g kg^?1) and Mg (MR: 220–690 g kg^?1), but would be good source of K, Ca and P. Most fish were also deficient in Fe, Zn and Cu, although the copper content would be the most affected (MR: 3–130 g kg^?1). Fish and krill meals showed a high content of Ca and P, although both would be deficient in Na (MR: 440–470 g kg^?1) and Cu (130–540 g kg^?1), along with K, Fe and Zn in krill and Mg and B in fish. Among the plant meals, sunflower and soybean were the most appropriate, presenting higher total content of minerals and MRs above 1000 g kg^?1 for all minerals, except Na, Cu and Zn.     

饵料对稚幼参生长变色的影响

报告了藻粉,浮泥,人工配合饵料,混合饵料对稚幼长岛县牝一海水育苗场变色的影响。经３个胸月的投喂试验。结果：人工配合饵料组稚幼参体长,体重增长较快,纯藻粉组,浮泥组投喂效果都较差。藻粉中添加部分“海丰”牌饲料预混剂和３０％的浮泥,对稚参有明显的助长作用,日均增长,增重是纯藻粉组的２倍以上,且明显快于人工配合饵料组。     

Practical Comparison of Commercial Starter Diets for Feed Training Largemouth Bass Fingerlings

We compared performance (growth, survival, and condition) of northern largemouth bass Micropterus salmoides salmoides fingerlings fed one of three commercial starter feeds: Otohime Marine Weaning (OMW; Marubeni Nisshin Feed), Bio-Oregon BiVita Fry (BVF; Bio-Oregon), and Purina Aquamax Starter (PAS; PMI Nutrition International LLC). Nine 833-L circular tanks, connected in parallel to a recirculation system, were stocked with 465 fish (1.4 kg), each to provide a rearing density of 1.1 fish/L. Water temperature was maintained at 27°C, and photoperiod was 15:9 h light:dark. Feed sizes (1.5–1.6 mm) were comparable and had similar protein composition (48%–50%). Feed was dispensed by vibratory feeders at a rate of 5% BWPD from 0730 h to 2130 h every 0.5 h for a total of 29 feedings per day (trial duration = 22 days). Overall performance was best for fish fed OMW, followed by BVF, then PAS. The PAS feed resulted in significantly lower growth, survival, and condition factor (P ≤ 0.05). Though not statistically significant, the BVF feed resulted in lower growth, condition factor, and survival than OMW (P > 0.05). Performance measures were positively correlated with crude fat and negatively correlated with protein to energy ratio of feeds. The OMW or BVF diets may be more appropriate for intensive culture when the artificial feed is the sole food supply, while the PAS diet may be more suitable for extensive culture as a supplemental food source.     

红鳍东方鲀开口饵料筛选试验

本文选择水产育苗常用的幼体开口饵料──小球藻、轮虫、卤虫幼体、蛋黄对初孵红鳍东方进行开口饵料筛选试验。结果表明：用小球藻和轮虫混合投喂效果最好,其余依次为轮虫、卤虫幼体、蛋黄。     

Cyclical feed deprivation and refeeding fails to enhance compensatory growth in Nile tilapia, Oreochromis niloticus L.

A 12-week experiment was carried out to evaluate compensatory growth of 6.6 g Nile tilapia Oreochromis niloticus L. under three cyclical regimes of feed deprivation and refeeding. The deprivation and refeeding regimes included four cycles of 1 week of deprivation and 2 weeks of refeeding (S1F2), two cycles of 2 weeks of deprivation and 4 weeks of refeeding (S2F4) and one cycle of 4 weeks of deprivation and 8 weeks of refeeding (S4F8). A group of fish fed to satiation twice daily throughout the experiment served as control. At the end of the refeeding periods, fish deprived and refed cyclically had higher feed intake and specific growth rates (SGR), but lower body weight, than that of the control fish. There was no significant difference in feed efficiency ratio (FER) between the control and fish subjected to feed deprivation during the refeeding periods, and nitrogen retention efficiency (NRE) was not different between any two treatments throughout the experiment. At the end of the experiment, fish subjected to feed deprivation had lower body weight but similar body composition, relative to those of the control fish. No significant differences were found in final body weight, NRE and body composition between the fish subjected to different cycles of deprivation and refeeding, but the fish subjected to one cycle of deprivation and refeeding exhibited high mortality. Our results indicate that partial growth compensation induced by various cycles of feed deprivation and refeeding does not confer a huge advantage in terms of enhancing the production efficiency and reducing the nitrogen waste output in Nile tilapia farming 29–30 °C.     

An evaluation of potential diets for the culture of postpueruli spiny lobsters Panulirus argus (Palinuridae)

Provision of a suitable feed is paramount for the ongoing success of spiny lobster culture. This study compared and evaluated the performance of seven diets for first instar juvenile spiny lobster Panulirus argus [5–6 mm carapace length (CL)] based on growth rates, survival, and feed conversion ratio. Results demonstrated that a seafood-based juvenile formulation produced the fastest growth rate (3.49% weight gain day⁻¹ and 0.90% CL increase day⁻¹ over a 28-day period). These growth rates were also reflected by a low feed conversion rate (3.04) for this formulated feed. Similar results were also obtained for juveniles fed a frozen seafood diet, however, frozen brine shrimp, Artemia salina (both enriched and un-enriched), frozen enriched mysis shrimp, a dry pellet, and a meal-based juvenile formulation did not produce consistent growth rates. Survival rates ranged between 38% and 85% and demonstrate that juvenile lobsters have better likelihoods of survival in captive culture environments compared to the wild. Although further nutritional refinement is recommended, the results from this research have significant implication for the possible expansion of juvenile spiny lobster growout to a larger scale.