Effects of traditional Chinese medicine on immune responses in abalone, Haliotis discus hannai Ino

A traditional Chinese medicine (TCM) preparation was formulated from orange peel (Pericarpium Citri Reticulatae), hawthorn (Crataegus pinnatifida), astragalus (Astragalus membranaceus (Fisch.) Bunge), pilose asiabell root (Radix codonopsis), indigowoad root (Radix isatidis), taraxacum (Herba taraxaci) and malt (Fructus Hordei Germinatus) at a weight ratio of 1:1:1.5:1.5:1.5:1.5:2. A feeding experiment was conducted to determine the effects of TCM on innate immunity of abalone, Haliotis discus hannai Ino. Artificial diets containing 1%, 3%, 5% TCM preparation, 1% hawthorn or 1% astragalus, respectively, were fed to juvenile abalone (initial weight 10.38+/-2.51 g; initial shell length 44.15+/-4.15 mm) for 80 days. A TCM-free diet was used as a control. Each diet was fed to three replicate groups of abalone using a randomized design. The results indicated that phagocytic activity was significantly higher in abalone fed 3%, 5% TCM preparation, 1% astragalus or 1% hawthorn (P<0.05). Respiratory burst activity was significantly higher in abalone fed 1%, 3%, 5% TCM preparation, 1% astragalus or 1% hawthorn (P<0.05). Agglutination titre was significantly higher in abalone fed 5% TCM preparation (P<0.05). Weight gain ratio (WGR), daily increment in shell length (DISL), total haemocyte count (THC), plasma protein concentration, and the activity of acid phosphatase (ACP) were not significantly affected by the TCM preparation (P>0.05). These results indicate that TCM preparation can modulate the immunity of H. discus hannai, and it is very possible that TCM might be used as immunostimulants in abalone farming.     

Effects of nutrient enrichment and biochemical composition of diets of Palmaria mollis on growth and condition of Japanese abalone, Haliotis discus hannai and red abalone, Haliotis rufescens

Two growth experiments were conducted with juvenile red abalone, Haliotis rufescens and Japanese abalone, Haliotis discus hannai. The first experiment was set up to determine if nutrient levels used for co-culture of the Rhodophyte, Pacific dulse (Palmaria mollis) directly affected abalone growth. No significant differences (ANOVA; P=0.117) were found in growth of abalone cultured in either ambient seawater alone or seawater supplemented with different NaNO₃ loads (1176, 1765, 2353, and 2942 μM day⁻¹ NO₃-N), NaH₂PO₄ (83.3 μM day⁻¹ PO₄⁻), and a modified version of Guillard and Ryther's [Gran. Can. J. Microbiol. 8, (1962) 229] f medium containing Fe, Zn, Mn, Cu, Mo, and Co.The second experiment was designed to determine the effect of different nutrient levels on the nutritional value of P. mollis when fed to abalone. P. mollis was cultured with different NaNO₃ loads (1176, 1765, 2353, and 2942 μM day⁻¹ NO₃-N) and NaH₂PO₄ (83.3 μM day⁻¹ PO₄⁻) in the presence or absence of f medium trace metals (Fe, Zn, Mn, Cu, Mo, and Co). H. discus hannai showed the highest LGR and SGR when fed on P. mollis supplemented with nitrate loads ranging from 1176 to 2353 μM day⁻¹ NO₃-N. In contrast, H. rufescens showed the highest linear growth rate (LGR) when fed on P. mollis supplemented with higher nitrate loads of 2353 to 2942 μM day⁻¹ NO₃-N, while nitrate load had no significant effect on specific growth rate (SGR). Both abalone species grew better on P. mollis supplied with 0.75f+Zn (day⁻¹) metal solution [Gran. Can. J. Microbiol. 8 (1962) 229] compared to those without trace metal additions, with H. discus hannai showing a further improvement in food conversion efficiencies (FCE).The present work shows that understanding and manipulating the culture environment of P. mollis can significantly affect growth, FCE, and daily food consumption (DFC) of H. discus hannai and H. rufescens.     

Comparison of growth and lipid composition in the green abalone, Haliotis fulgens, provided specific macroalgal diets

Lipid composition of abalone was examined over a one-year interval. A feeding trial was designed to cover a full reproductive cycle in young adult green abalone, Haliotis fulgens, consisting of five diet treatments: the macrophytic algal phaeophyte Egregia menziesii, rhodophyte Chondracanthus canaliculatus, chlorophyte Ulva lobata, a composite of the three algae and a starvation control. The lipid class, fatty acid, sterol and 1-O-alkyl glyceryl ether profiles were determined for foot, hepatopancreas/gonad tissues and larvae. The major fatty acids were 16:0, 18:0, 18:1(n-7)c, 18:1(n-9)c, 20:4(n-6), 20:5(n-3) and 22:5(n-3), as well as 14:0 for abalone fed brown and red algae. 4,8,12-Trimethyltridecanoic acid, derived from algae, was detected for the first time in H. fulgens (hepatopancreas complex, 1.2–13.9%; larvae, 0.5% of total fatty acids). Diacylglyceryl ethers were present in larvae (0.6% of total lipid). The major 1-O-alkyl glycerols were 16:0, 16:1 and 18:0. Additionally, 18:1(n-9) was a major component in hepatopancreas/gonad and larvae. The major sterol was cholesterol (96–100% of total sterols). Highest growth rates were linked to temperature and occurred in abalone fed the phaeophyte E. menziesii (43 μm·day^–1, 56 mg·day^–1 yearly mean), an alga containing the highest levels of C₂₀ polyunsaturated fatty acids and the highest ratio of 20:4(n-6) to 20:5(n-3). This study provides evidence of the influence of diet and temperature on seasonal changes in abalone lipid profiles, where diet is most strongly related to body mass and temperature to shell length. The allocation of lipids to specific tissues in green abalone clarifies their lipid metabolism. These results provide a basis for improving nutrition of abalone in mariculture through formulation of artificial feeds.     

Effects of dietary vitamin K on survival, growth, and tissue concentrations of phylloquinone (PK) and menaquinone-4 (MK-4) for juvenile abalone, Haliotis discus hannai Ino

The experiment was conducted to investigate the effects of dietary vitamin K on survival, growth and tissue vitamin K concentrations of abalone, Haliotis discus hannai. Eight purified diets were formulated to provide a series of graded levels of menadione sodium bisulfite (MSB) (0-320 mgkg(-1) diet). The brown alga, Laminaria japonica, was used as a control diet. Abalone juveniles of similar size (mean weight 1.18+/-0.04 g; mean shell length 18.65+/-0.18 mm) were distributed in a flow-through system using a completely randomized design with nine treatments and three replicate groups per treatment. Animals were hand-fed the appropriate diets once daily at 17:00 for a 120-day period. Survival and carcass composition were not significantly affected by the dietary treatments (P>0.05). Significantly lower growth rate was found in abalone fed diet supplemented with antibiotic (suphaguanidine) than in those fed the other diets, but no significant difference in growth rate related to dietary level of MSB was observed. The concentrations of menaquinone-4 (MK-4) in muscle and viscera increased with increasing dietary MSB up to 10 mgkg(-1). No phylloquinone (PK) was detected in tissues except that the abalone fed the control diet, Laminaria japonica, produced a relatively high level of PK. It seemed to be that the 10-mg MSBkg(-1) diet is sufficient to that allowing the maintenance of 'steady-state' tissue concentration in juvenile abalone. Dietary MSB was converted to MK-4 in abalone. Either MK-4 or PK deposited in the body is derived from food.     

Effects of wild and farm-grown macroalgae on the growth of juvenile South African abalone Haliotis midae Linnaeus

The effect of various macroalgal diets on the growth of grow-out (>20 mm shell length) South African abalone Haliotis midae was investigated on a commercial abalone farm. The experiment consisted of four treatments: fresh kelp blades (Ecklonia maxima (Osbeck) Papenfuss) (c. 10% protein); farmed, protein-enriched Ulva lactuca Linnaeus (c. 26% protein) grown in aquaculture effluent; wild U. lactuca (c. 20% protein); and a combination diet of kelp blades + farmed U. lactuca. Abalone grew best on the combination diet (0.423 ± 0.02% weight d^?1 SGR [specific growth rate]; 59.593 ± 0.02 ?m d^?1 DISL [daily increment in shell length]; 1.093 final CF [condition factor]) followed by the kelp only diet (0.367 ± 0.02% weight d^?1 SGR; 53.148 ± 0.02 ?m d^?1 DISL; 1.047 final CF), then the farmed, protein-enriched U. lactuca only diet (0.290 ± 0.02% weight d^?1 SGR; 42.988 ± 0.03 um d”¹ DISL; 1.013 final CF) that in turn outperformed the wild U. lactuca only diet (-0.079 ± 0.01% weight d^?1 SGR; 3.745 ± 0.02 ?m d”^?1 DISL; 0.812 final CF). The results suggest that protein alone could not have accounted for the differences produced by the varieties of U. lactuca and that the gross energy content is probably important.     

冬季饥饿再投喂对菲律宾蛤仔生长、存活和生化组成的影响

2007年12月—2008年4月,在冬季低温（水温3.0 ℃～4.2 ℃、盐度25～27、pH 7.90～8.16）条件下,采用饥饿时间不等、恢复投喂时间相同的方式,研究了饥饿再投喂对不同规格菲律宾蛤仔生长、存活及体组分的影响.结果表明：在冬季低温条件下,各试验组菲律宾蛤仔生长性状的差异不明显;其对饥饿的耐受能力随着蛤仔规格的增大而升高;存活率随着饥饿时间的延长而降低,但整个试验过程中未出现不可逆点.从较大规格菲律宾蛤仔（壳长7 mm）的体组分上看：菲律宾蛤仔水分、脂肪含量随着饥饿时间的延长而下降;蛋白质含量在饥饿前期随着脂肪的消耗而上升,后期因脂肪的过度消耗开始被利用而下降;灰分含量在整个试验过程中的变化不显著.     

Effects of food quality on growth and biochemical composition of a calanoid copepod,Argyrodiaptomus furcatus,and its importance as a natural food source for larvae of two tropical fishes

Growth, reproduction and biochemical composition were analyzed for the copepod Argyrodiaptomus furcatus fed on the alga Ankistrodesmus gracilis grown in different media. The ingestion of this copepod by larvae of two species of tropical fishes was also evaluated. The mean peak density of the copepod population was 1369 individuals l^–1 for all four diets used, and the highest was 1387 individuals l^–1 on diet ARV (algae + ration + vitamins). A small copepod, A. furcatus tends to have a short life span. The smallest females did not attain maturity in the shortest time on all diets used. Food quality may play a major role in the dynamics of the biochemical composition of this copepod. Argyrodiaptomus furcatus was a more important food item for larvae of tambaqui (Colossoma macropomum) than of pacu (Piaractus mesopotamicus). However, it made up a large part of the gut contents of larvae of both species.     

Changes in amino acid content of an algal feed species (Navicula sp.) and their effect on growth and survival of juvenile abalone (Haliotis rubra)

The growth and survival of juvenile Haliotis rubra, when fed with the diatom Navicula sp. cultured in f/2 medium containing combined nitrogen at 24.71 mg NO₃-N L^–1 (high), 12.35 mg NO₃-N L^–1 (standard) or 2.47 mg NO₃-N L^–1 (low), were compared in a 33-day trial. The alga in the low nitrogen medium contained 37% less total amino acid than that in the high and standard nitrogen media. There was a slightly greater reduction in essential amino acids (40%) compared to non-essential amino acids (35%). Juvenile abalone feeding on Navicula grown in medium with low nitrate and lower total amino acid content grew more slowly than when fed on the same species grown in standard or higher nitrogen medium with a higher amino acid content. The growth rate of juveniles was highest (43 m d^–1) in the high nitrate treatment followed (40 m d^–1) by the standard nitrate treatment and lowest (31 m d^–1) in the low nitrate treatment. The survival of the juveniles was also effected by the diet. Survival was better in the high and standard nitrogen media (88%) than the low nitrogen medium (75%). The results suggest that in order to achieve uniformity in nutritional quality of diatoms and good growth of abalone juveniles in commercial abalone nurseries, the nitrogen concentration in tanks should be monitored and additional nitrate added to provide an optimum concentration of between 2 and 12 mg NO₃-N L^–1.     

The relative food value and biochemical composition of five phytoplankton diets for queen conch, Strombusgigas (Linne) larvae

The food value of five phytoplankton diets for queen conch larvae, Strombus gigas (Linne), was estimated in two feeding experiments. The species Isochrysis aff. galbana clone T.ISO, Prorocentrum minimum (Pavillard) Schiller (ex. P. marialebouriae) clone EXUV, Emiliania huxleyi (Lohm.) Hay & Mohler (ex. Coccolithus huxleyi) clone Bt-6, and Heterocapsa pygmacea (Loeblich) Schmidt & Sherley clone Gymno all supported rapid growth and high survival of queen conch larvae. Dunaliella tertiolecta (Butch.) clone DUN supported only minimal growth. The total lipid content and fatty acid composition of all five algal diets were analysed. The best diets had above average lipid content and contained the long-chained polyunsaturated fatty acids eicosapentaenoic (20:5ω3) and/or docosahexaenoic (22:6ω3) acids.     

Effects of different vertebrate growth factors on primary cultures of hemocytes from the gastropod mollusc,Haliotis tuberculata

Summary— A useful experimental system from primary cultures of hemocytes from Haliotis tuberculata has been established. Six days after initiation of the culture, the viability of hemocytes remained constant as measured by the MTT assay. In addition, hemocytes showed physiological responses as judged by protein and DNA syntheses in response to treatment with vertebrate growth factors. Porcine insulin and human epidermal growth factor (EGF) stimulated [³H]-leucine and [³H]-thymidine incorporation in hemocytes in a dose-dependent manner. No additive effect of insulin and EGF is observed either for [³H]-leucine or for [³H]-thymidine incorporation. The response of primary cultures of abalone hemocytes to vertebrate growth factors confirms their growth potential in vitro and provides a suitable model for further studies on regulation of the control of cellular processes such as cell growth, differentiation and migration in invertebrate cells.     

Effects of temperature and growth phase on lipid and biochemical composition of Isochrysis galbana TK1

The lipid and biochemical composition of the haptophyte Isochrysis galbana TK1 was examined. Cultures were grown at 15 °C and 30 °C, and harvested in the exponential and early stationary growth phases. Carbohydrate and protein content varied at the two culture temperatures and growth phases. The highest protein content was found at the exponential growth phase at 15 °C, and the highest carbohydrate content was found at the stationary phase at the same culture temperature. Lipid accumulated in the stationary growth phase and its content was higher at 30 °C than at 15 °C regardless of the growth phase. The neutral lipids were the major class of lipid found in all the cultures. The stationary phase culture had a higher proportion of neutral lipids than the exponential phase culture and the proportion decreased slightly when culture temperature was increased from 15 °C to 30 °C. Phospholipid levels remained constant at the two temperatures, but slightly decreased in the stationary phase. Glycolipids in the exponentially growing cells were higher than those from stationary growth phase and increased with temperature. Polyunsaturated fatty acids (PUFAs) predominated in glycolipids and phospholipids. Cells grown at 15 °C contained higher proportion of 18:3 (n–3) and 22:6 (n–3) with a corresponding decrease in 18:2 (n–6), monounsaturated and saturated fatty acids. This revised version was published online in August 2006 with corrections to the Cover Date.     

Effects of nutrient and light limitation on the biochemical composition of phytoplankton

Three marine phytoplankters (Isochrysis galbana, Chaetoceros calcitrans andThalassiosira pseudonana), commonly used in the culture of bivalve larvae, were grown in batch or semi-continuous cultures. Changes in protein, carbohydrate, lipid and some fatty acids were measured as growth became limited by nitrogen, silicon, phosphorus or light. Under N starvation (2 d) the % lipid remained relatively constant, while% carbohydrate increased and% protein decreased in all 3 species compared to cells growing under no nutrient limitation. Under Si starvation (6 h) there was no change in lipid, protein or carbohydrates. The amount of two fatty acids, 20 : 53 and 22 : 63 remained relatively constant under N, P and Si starvation, exept for a sharp drop in the cells of P-starvedT. pseudonana. However, there were pronounced species differences withI. galbana containing significantly less 20 : 5 3 thanC. calcitrans orT. pseudonana. Under light limitation the amount of lipid per cell showed no consistent trend over a range of irradiances for all 3 species. The amount of N per cell (an index of protein content) as a function of irradiance, was relatively constant forI. galbana andT. pseudonana, while the amount of N per cell was lower under low irradiances forC. calcitrans. These examples of changes in protein, carbohydrate, lipid and certain fatty acids under nutrient (N, Si or P) or light limitation, emphasize the importance of knowing the phase (e.g. logarithmic vs stationary) of the growth curve in batch cultures, since the nutritional value of the phytoplankters could change as cultures become dense and growth is terminated due to nutrient or light limitation.Presented at the XIIIth International Seaweed Symposium, University of British Columbia, Vancouver, Canada, August 1989.     

Effects of starvation on growth, survival, and body biochemical composition among different sizes of Manila clam Ruditapes philippinarum

A study was conducted to investigate the impact of starvation on different sizes of Manila clam Ruditapes philippinarum (0.66 ± 0.11, 2.12 ± 0.38, and 11.65 ± 0.84 mm in shell length, respectively) in the summer of 2008. Different size clams were starved for 7, 15, 30, 45, and 60 d, respectively, and followed by refeeding for 30 d. During the study, the water temperature ranged 26.2–28.4 °C, salinity 22–24‰, and pH 7.80–8.12. Compensatory growth occurred in the smallest size-group after 7 and 15 d of starvation, respectively. The point-of-no-return (PNR₅₀) was determined to be 18.7 d. However, no compensatory growth was noted in the medium size-group, and the PNR₅₀ for this group was 25.2 d. The complete compensatory growth was observed for the largest size-group following food depravation for 7 and 30 d, respectively. In the same group, over-compensatory growth occurred 15 d post-starvation. The PNR₅₀ for the largest size-group was 46.3 d. The survival rate of different groups decreased as the starvation time prolonged. To discuss the change in body biochemical composition of individuals in the process of starvation and refeeding, the biochemical composition of the largest group individuals at different stages was determined. There were no significant differences in moisture and ash concentrations of the largest size-group during starvation and refeeding (P > 0.05). The relative body protein content increased as the starvation period prolonged and the level returned to normal after refeeding. The lipid content of the clam at the end of starvation was significantly lower than the initial level (P < 0.05), and remained below the initial level at end of the refeeding period.     

Effects of starvation on growth, survival, and body biochemical composition among different sizes of Manila clam Ruditapes philippinarum

A study was conducted to investigate the impact of starvation on different sizes of Manila clam Ruditapes philippinarum (0.66 ± 0.11, 2.12 ± 0.38, and 11.65 ± 0.84 mm in shell length, respectively) in the summer of 2008. Different size clams were starved for 7, 15, 30, 45, and 60 d, respectively, and followed by refeeding for 30 d. During the study, the water temperature ranged 26.2–28.4 °C, salinity 22–24‰, and pH 7.80–8.12. Compensatory growth occurred in the smallest size-group after 7 and 15 d of starvation, respectively. The point-of-no-return (PNR₅₀) was determined to be 18.7 d. However, no compensatory growth was noted in the medium size-group, and the PNR₅₀ for this group was 25.2 d. The complete compensatory growth was observed for the largest size-group following food depravation for 7 and 30 d, respectively. In the same group, over-compensatory growth occurred 15 d post-starvation. The PNR₅₀ for the largest size-group was 46.3 d. The survival rate of different groups decreased as the starvation time prolonged. To discuss the change in body biochemical composition of individuals in the process of starvation and refeeding, the biochemical composition of the largest group individuals at different stages was determined. There were no significant differences in moisture and ash concentrations of the largest size-group during starvation and refeeding (P > 0.05). The relative body protein content increased as the starvation period prolonged and the level returned to normal after refeeding. The lipid content of the clam at the end of starvation was significantly lower than the initial level (P < 0.05), and remained below the initial level at end of the refeeding period.     

摄食水平和投喂频率对大菱鲆幼鱼生长及生化成分的影响

以大菱鲆幼鱼(7.56±0.03 g)为试验对象,在水温17～19℃下,设计了4个摄食水平梯度(1.0％、1.5％、2.0％和饱食)和3个投喂频率梯度(1、2和3次·d-1),探讨了不同摄食水平和投喂频率对其生长及生化成分的影响.结果表明:随着摄食水平的升高,大菱鲆幼鱼的终末体重、相对增重率和摄食率显著升高(P＜0.05);特定生长率随摄食水平的增加呈线性升高;湿重、干重、蛋白质和能量转化效率出现先升高后降低的趋势;摄食水平对鱼体的体成分和组间表观消化率无显著影响(P＞0.05);不同投喂频率下,终末体重、相对增重率、特定生长率及转化效率呈先升高再降低的趋势,在2次·d-1时取得最大值;投喂频率对鱼体的体成分和组间表观消化率无显著影响(P＞O.05).     

Effect of feeding and lack of food on the growth, gross biochemical and fatty acid composition of juvenile catfish

The effect of feeding and starvation on growth, gross body composition and fatty acid composition of body muscle and liver were investigated in juvenile African catfish ( Clarias gariepinus ). The relative composition of fatty acids was influenced by starvation. In both liver and muscle there were marked relative decreases of 14: 0, 16: 1n9 and 18: 1n9 fatty acids and relative increases of 20: 5n3 and 22: 6n3 when these were compared to the controls. Preference of utilization of fatty acids from liver and body muscle during starvation was highest for 14: 0>16: 1n9>18: 1n9 and conservation highest for 22: 6n3>20: 5n3. The changes of these fatty acids were smaller in muscle than in the liver.     

光强及氮浓度对丝状绿藻双星藻生长及生化组成的影响

[背景]环境因子和营养因子对微藻的生长和生化组成都有显著的影响,其中光强和氮浓度是最重要的两个条件。[目的]研究不同光强和初始氮浓度对丝状绿藻-双星藻(Zygnema sp.)生长及生化组成的影响。[方法]采用改良的BBM培养基,设置了两组光强[100μmol/(m²·s)和300μmol/(m²·s)]和6种初始氮浓度(3、6、9、12、15和18 mmol/L)在柱状光生物反应器中对双星藻进行培养。[结果]在高光强条件下[300μmol/(m²·s)],12 mmol/L初始氮浓度最有利于双星藻生物质的积累,其最高生物量可以达到6.60 g/L,而初始低氮浓度(3 mmol/L)则促进了油脂和脂肪酸的积累,油脂最高含量占干重的32.13%,且脂肪酸组成主要包括棕榈酸(C_16:0)、油酸(C_18:1)、亚油酸(C_18:2)和亚麻酸(C_18:3),其中油酸含量最高达到总脂肪酸含量的55.01%;在低光强条件下[100μmol/(m     

Seasonal and interspecific variation in the biochemical composition of some British fern species and their effects on Spodoptera littoralis larvae

Fern-feeding insects in Britain are mainly found on mature fronds in late summer. Six fern species (Dtyopteris filix-mas, D. dilatata, D. borreri, Phyllitis scolopendrium, Polyslkhum setiferum and Polypodium vulgare) were analysed for fibre, lignin, cellulose, tannins, cyanogenesis and thiaminase activity in an attempt to determine the biochemical basis for this seasonal pattern of attack. A bioassay was also carried out, using frond material incorporated in the diet of Spodoptera littoralis, to determine the effects of seasonal changes in fern toxins on a non-adapted, insect herbivore. The young fronds of all six species had a high protein content and low fibre-lignocellulose; protein levels decreased and cell wall materials increased as the fronds matured. Tannin concentrations and thiaminase activity showed a less consistent seasonal pattern. Tannins were present in the highest concentration in the young fronds of D. borreri, Polystichum and Polypodium and decreased with season; D. dilatata, Polystichum and Polypodium showed a similar pattern of thiaminase activity. The other species showed no strong seasonality in the levels of either tannins or thiaminase. No cyanogenic activity was detected in any of the fern species. Frond material from all six species decreased survivorship and growth rates of Spodoptera larvae. Larval performance and growth on diets containing fern material from young immature fronds was generally poorer than on diets containing material from mature fronds, collected later in the season. Neither tannin concentrations nor thiaminase activity levels closely corresponded to the observed interspecific and seasonal patterns of larval development and mortality, and other toxins must be involved. It is concluded that ferns are highly toxic to non-adapted herbivorous insects but the effects on adapted species are unknown. The restricted seasonal occurrence of a small number of insect species exhibiting specialized feeding habits suggests, however, that biochemical properties of the ferns determine this pattern of attack and limit the number of species which are able to exploit ferns as food resources.     

Effect of lysophospholipids in diets differing in fat contents on growth performance,nutrient digestibility,milk composition and litter performance of lactating sows

It is well known that energy plays an important role in sow growth and development. Increasing the utilization of lipids will be beneficial to sows. Emulsifiers are substances which stabilize mixtures and prevent oil and water from separating, thereby enhancing the digestion of lipids. This study was conducted to evaluate the effect of dietary emulsifier (lysophospholipids (LPL)) supplementation in diets differing in fat contents on growth performance, nutrient digestibility and milk composition in lactating sows, as well as performance and fecal score in piglets. A total of 32 multiparous sows (Landrace×Yorkshire) were used in a 21-day experiment. On day 110 of gestation, sows were weighed and moved into the farrowing facility, randomly assigned in a 2×2 factorial arrangement according to their BW with two levels of LPL (0 and 30 mg/kg) and two levels of fat (4.75% and 2.38% fat; 13.66 and 13.24 MJ/kg). BW loss and backfat thickness loss were decreased (P<0.05) by LPL supplementation. Backfat thickness at weaning was higher (P<0.05) in sows fed LPL supplementation diets. The apparent total tract digestibility of dry matter, nitrogen, gross energy and crude fat in sows fed LPL diets was increased (P<0.05) compared with those fed non-LPL diets. Sows fed the high-fat diets had higher (P<0.05) milk fat on day 10 and milk lactose on day 20 than those fed the low-fat diets. Milk fat and lactose concentrations in LPL supplementation treatments was increased (P<0.05) compared with non-LPL treatments on day 10 and day 20, respectively. Positive interaction effects (P<0.05) between fat and LPL were observed for milk fat concentration on day 10. In conclusion, LPL addition decreased BW loss and backfat thickness loss, improved nutrient digestibility and milk fat as well as milk lactose concentrations. In addition, there was a complementary positive effect of dietary fat and LPL supplementation on milk fat concentration in lactating sows.     

Field studies on the ureogenic gulf toadfish in a subtropical bay. I. Patterns of abundance, size composition and growth

Opsanus beta abundance in Biscayne Bay, Florida, varied significantly depending on site and season. O. beta catch per unit effort (cpue) was highest in southern study sites which tended to provide the combination of shallow mean depth, nocturnally high levels of dissolved oxygen, and Thalassia -dominated substrate. Significant seasonal differences in abundance were restricted to the three sites where O. beta cpue tended to be highest; two of these sites shared the same pattern of in crease during the cool-dry season (November-April), followed by a return to lower levels during warm-wet season (May-September). Dramatic seasonal abundance increases could not be ascribed to large influxes of immature fish. Rather, size composition data suggested sexually mature individuals moved seasonally among habitats, possibly for reproductive purposes. Modal analysis of length-frequency data followed by nonlinear regressions yielded preliminary values for the von Bertalanffy growth parameters K and t₀ , given that L_σ = 300 mm. Possible reasons for O. beta growing slower and attaining a smaller maximal size than its temperate congener, O. tau , are discussed.