The significance of ungulocoriitis septica (traumatic) in the toe of the bovine claw

Due to the specific anatomy at the toe of the claw, inflammation of the corium at this site is characterised by a rapid spread to the distal phalanx. Radiography is important for the diagnosis and essential for determining the prognosis. In the early stage of the condition, therapy consists of correct wound care and relieving the affected claw from weight-bearing by applying an orthopaedic shoe to the partner claw. Resection of the claw toe is indicated if there is evidence of osteolysis. The postoperative healing period frequently lasts more than two months; there is a tendency to hypergranulation. Deformation of the claw due to irregular horn growth following surgery may occur. Compared to the treatment by amputation, the economic life of the patient is longer following resection and there are no restrictions on use.     

The treatment of insertion desmopathy in the metatarsus of horses

Metacarpal or metatarsal exostoses were diagnosed in 112 horses used for sport purposes between January 1976 to December 1987. Fourteen of these patients were treated surgically by subperiosteal removal of the exostosis. All animals which could be followed up had returned to their original use. The average time of use after discharge from the clinic was 38.4 months. Surgery was successful in completely removing the exostoses in 58.3% of these horses. The indications for anaesthesia and resection of the ulnar nerve are discussed.     

Metacarpal and metatarsal fractures in cattle. Treatment and results

94 cattle with 97 metacarpal or metatarsal fractures were presented at the Department of Veterinary Surgery of the Ludwig-Maximilians-Universit?t, Munich, between 1970 and 1987. The cause of fracture was incorrect traction during assisted delivery in almost one third (30.9%) of cases. Eighty-two animals were treated. 59 out of 73 cattle treated conservatively and 7 out of 9 which were operated, could be healed. In 38 animals the fracture healed without malpositioning; 28 developed a shortening or bending of the affected limb, which, with the exception of one case, did not functionally impair the animals. Complications occurred in 22 patients (= 26.9%); in closed fractures the reason was predominantly due to dislocation of the fragments within the cast, whereas an osteomyelitis was usually the cause in the case of the open fractures.     

Growth,Processing Measurements,Tail Meat Yield,and Tail Meat Proximate Composition of Male and Female Australian Red Claw Crayfish,Cherax quadricarinatus,Stocked into Earthen Ponds

Abstract

Small (0.7 g) juvenile red claw, Cherax quadricarinatus, were stocked in earthen ponds (0.04 ha) in Kentucky and grown for 86 days so that measures of growth, survival, processing characteristics, and proximate composition of tail muscle in male and female Australian red claw crayfish could be obtained. A commercial marine shrimp was fed to all red in two separate feedings, each consisting of one-half of the total daily ration between 0800-0830 and between 1530-1600 hours for the duration of the culture period. Total weight and number of red claw from each pond were recorded at the harvest. Forty red claw from each sex were randomly sampled, chill-killed by lowering the body temperature in an ice-bath, and frozen (-20°C) for processing measurements and proximate composition. Red claw were removed from the freezer, thawed, individually weighed to the nearest 0.01 g, and then were hand-processed so that weights of chelae, tail, and tail muscle were obtained to the nearest 0.01 g. After 87 days, red claw had a final average individual weight of 59.6 g, weight gain of 8,413%, survival of 64.0%, yield of 903 kg/ha, and feed conversion ratio (FCR) of 4.63. When analyzed by sex, males had significantly (P < 0.05) higher final individual weight (71.05 g) compared to females (53.65 g); higher (P < 0.05) chelae weight (13.1 g for males compared to 6.84 g for females); higher tail weight (25.53 g for males compared to 20.38 g for females); higher tail muscle weight (18.99 g for males compared to 14.89 g for females); and higher cephalothorax weight (32.41 g for males compared to 26.44 g for females; Table 2). There were no significant differences (P > 0.05) in the percentage moisture, protein, lipid, fiber, and ash in the tail muscle of male and female red claw when analyzed either on a wet-weight basis and averaged 81.0%, percentage protein averaged 16.46%, percentage lipid averaged 0.16%, fiber averaged 0.1%, and percentage ash averaged 1.42%. Results from the present study indicate that red claw can be grown as a commercial aquaculture species in locations with limited growing seasons, and that male red claw grow larger, have larger chelae, and higher tail muscle weights compared to females so that it might be economically advantageous to stock all-male populations of red claw in ponds to achieve maximum production. Further research on growth and processing yields of red claw should be conducted to assist the industry.     

Use of Alfalfa Hay, Compared to Feeding Practical Diets Containing Two Protein Levels, on Growth, Survival, Body Composition, and Processing Traits of Australian Red Claw Crayfish, Cherax quadricarinatus, Grown in Ponds

Juvenile red claw, Cherax quadricarinatus, were obtained from a commercial supplier and stocked into twelve 0.04‐ha ponds with an average water depth of approximately 1.1 m at a rate of 1100 red claw per pond (27,170 red claw/ha). Mean stocking weight (±SD) was 6.25 ± 3.0 g. Three replicate ponds were randomly assigned to each of the four treatments. In Treatment 1 (TRT1), red claw were stocked into ponds to which dried alfalfa hay (forage) was added at a rate of 500 kg/ha/mo; Treatment 2 (TRT2) consisted of red claw being fed a prepared diet containing 13% protein; in Treatment 3 (TRT3), red claw were fed a diet containing 13% protein at which had dried alfalfa hay been added at a rate of 500 kg/ha/mo; and in Treatment 4 (TRT4; control), red claw were fed a complete diet containing 28% protein. Water quality measurements were made three times weekly for dissolved oxygen and temperature (am , pm ), pH, total ammonia nitrogen, nitrite, and alkalinity averaging 7.17 mg/L, 8.96 mg/L, 25.5 C, 27.3 C, 8.68, 0.39 mg/L, 0.012 mg/L, and 106.5 mg/L, respectively. After 113 d, the final mean weight of red claw fed TRT3 was significantly (P < 0.05) higher (68.10 g) compared to that of red claw fed hay only (49.40 g) but not different from red claw fed TRT2 (56.03 g) and TRT4 (62.10 g). Likewise, red claw fed TRT3 had significantly higher percent weight gain (990%) compared to that of red claw fed hay only (690%) but not different from TRT2 (796%) and TRT4 (893%). Feed conversion ratio of TRT2, TRT3, and TRT4 and percent survival among all treatments did not differ significantly (P > 0.05), averaging 2.85 and 66.8%, respectively. Total yield of red claw fed TRT3 and TRT4 (968 and 952 kg/ha) was significantly (P < 0.05) higher compared to that of red claw fed hay only (617 kg/ha) but did not differ from red claw fed TRT2 (882 kg/ha). Tail meat yield of male red claw in TRT3 was significantly (P < 0.05) higher (17.3 g) compared to that of male red claw in TRT1 (12.7 g) and TRT2 (14.9 g) but not significantly different (P > 0.05) from male red claw in TRT4 (16.9 g). Tail meat yield of female red claw in TRT3 and TRT4 was significantly (P < 0.05) higher (14.2 and 13.9 g, respectively) compared to that of female red claw in TRT1 (10.5 g) and TRT2 (10.4 g). Tail muscle proximate compositions showed no significant differences (P > 0.05) in protein (wet weight basis) between males and females among treatments (diet) which averaged 16.2 and 14.6%; however, there were little to no significant differences in fat and ash between males and females among treatments. Results from this study indicate that pond‐cultured red claw stocked at 27,170 red claw/ha can be fed a practical diet containing 13% protein, with or without forage (alfalfa hay), compared to red claw fed a complete diet containing 28% protein; however, if alfalfa hay is added to the pond at 500 kg/ha/mo as the sole source of added nutrients, growth is reduced. Therefore, the use of alfalfa hay, in combination with a low‐protein pelleted diet may be a production method for pond‐grown red claw that may reduce costs for producers and thereby increase profits.     

Blepharoplasty after tumor ("cancer eye") removal from the eyes of cattle

A literature review of surgical techniques used for resection of periocular tumors with conservation of the eyelid is accompanied by a report of the author's personal experience with blepharoplasty in cattle. Included are 13 cases of Fleckvieh cows with squamous cell carcinoma. Five animals were without tumor recurrence after an average time of 10.7 months, while seven animals with recurrence of the neoplasm had mean survival time of 10.6 months. Those five cows had been slaughtered for unrelated problems, the others because of recurrence of the ocular tumor. One patient was slaughtered five days after surgery because of complications of wound healing.     

Indoor Spawning and Egg Development of the Red Claw Crayfish Cherax quadricarinatus

In 1991 and 1992, indoor hatchery experiments were conducted with red claw crayfish Cherax quadricarinatus a large tropical crayfish from northern Australia. Six fiberglass tanks were stocked with 40–190 g mature red claw crayfish at 10/m² and a 1:2 male to female ratio. Water temperature was maintained at 28 ± 1 C. Photoperiod was provided by natural daylight in 1991 and controlled lighting in 1992.
With natural lighting, monthly spawning rates (% of females spawning/month) ranged from an average of 15% during months with less than 12 h of light per day to over 35% in months with more than 12 h of light per day. Peak spawning occurred from May to July, too late to obtain juveniles for spring stocking. During the second year, photoperiod was increased from 10L:14D in December to 14L:10D in February and maintained at this level until July. Red claw spawning increased with increasing day length. Peak spawning rates of 50% per month and higher occurred from March to May. Spawning rates decreased dramatically after May, even though photoperiod and temperature remained constant. Eggs per spawn increased with an increase in female size. Fecundity average 7.3 juveniles per gram of body weight for females from 40 to 190 g, regardless of size. Egg color was useful for predicting stage of development.     

Partial and total replacement of fish meal with soybean meal and brewer's grains with yeast in practical diets for Australian red claw crayfish Cherax quadricarinatus

Three feeding studies were conducted to evaluate the effects of total replacement of fish meal (FM) with a combination of soybean meal (SBM) and brewer's grains with yeast (BGY) in diets for two separate strains of juvenile Australian red claw crayfish. In Experiment 1, three practical diets were formulated to be isonitrogenous (40% protein) and isocaloric (4.0 kcal available energy/g diet) and contained either 25%, 10%, or 0% fish meal. Variable percentages of SBM (35%, 46.8%, and 79.8%, respectively) and BGY-35 (0%, 30%, and 5%, respectively) replaced the fish meal. In Experiments 2 and 3, four practical diets were formulated to be isonitrogenous (40% protein) and isocaloric (4 kcal available energy/g diet) containing 24% or 0% fish meal. Diet 1 contained 24% fish meal, 23% SBM, and 0% BGY-35. A variable percentage of SBM (56.75%, 47.75%, and 40.75%, respectively) and BGY-35 (10%, 20%, and 30%, respectively) replaced the fish meal in the remaining three diets.

In Experiment 1, after 8 weeks, juvenile red claw fed all three diets had no significant difference (P>0.05) in final weight, percentage weight gain, or survival, which averaged 7.90 g, 3848%, and 83%, respectively. In Experiment 2, after 8 weeks, juveniles fed all four diets had no significant difference in final weight, percentage weight gain, or specific growth rate which averaged 11.46 g, 977%, and 3.08%/day, respectively. Percentage survival was not significantly different among treatments and averaged 79%. In Experiment 3, after 8 weeks, juvenile red claw fed all four diets had no significant difference in final weight, percentage weight gain, or specific growth rate which averaged 16.22 g, 457%, and 2.34%/day, respectively. Percentage survival was not significantly different among treatments and averaged 98%.

These results indicate that fish meal and shrimp meal can be totally replaced with soybean meal and BGY in diets for juvenile red claw crayfish. This may allow for less expensive diets by red claw producers, which may increase profitability.     

Observations on the Frequency of Claw Loss in the Crayfish Procambarus charkii

Abstract— The incidence of claw loss in the crayfish Procambarus clarkii was surveyed in two ponds. Pond 1 contained rice forage, and crayfish were trapped and removed three times per week. Pond C48 contained no supplemental forage, and no trapping occurred in the pond. In March claw loss in both ponds was similar with 87–91% of the population having both claws intact. Males and females showed no difference in the incidence of claw loss in either ponds. By May the abundant rice forage present in pond 1 during March had been depleted; however, the physical appearance of pond C48 changed little. In May claw loss was greater in pond 1 than pond C48; both males and females in pond 1 had a higher incidence of claw loss (increasing from 13% to 37%) than those in pond C48 (increasing from 9% to 17%). Claw loss in pond C48 males did not increase significantly; however, female claw loss increased approximately two-fold. In May hepatopancreas water content was significantly higher for crayfish from pond 1 when compared to pond C48, suggesting lower energy reserves. During times of environmental stress, such as decreased food availability, decreased structure, low oxygen or temperature extremes, regeneration may influence energy allocation to growth and possibly reproduction, especially if energy reserves are low. Thus, information on the incidence of claw loss and energy reserves in crayfish exposed to different pond conditions may be useful in the design of management strategies.     

Effect on Growth, Survival, and Fatty Acid Composition of Australian Red Claw Crayfish Cherax quadricarinatus Fed Practical Diets With and Without Supplemental Lecithin and/or Cholesterol

Red claw crayfish Cherux quadricarinatus is one of more than a hundred species of Australian freshwater crayfish. However, because of its rapid growth rate, communal and non‐burrowing behavior, ease of spawning, wide temperature and dissolved oxygen tolerance, and no free‐swimming larval stages, red claw may be the best candidate among the Australian crayfishes for semi‐intensive or intensive aquaculture in the United States. The objective of the study was to examine the effects of growth, survival, and fatty acid composition of newly‐hatched red claw when fed four practical diets with or without lecithin and cholesterol. However, little is known of its nutritional requirements or practical diet formulations. An 8‐wk feeding trial was conducted in a recirculating system with newly‐hatched juvenile (mean individual weight, 0.2 g) red claw, each stocked in separate plastic mesh culture units containing their own individual water line. Water was recirculated through biological and mechanical filters. Practical diets were formulated to be isonitrogenous (40% protein) and isocaloric (4 kcal available enerpy/g of diet) and contained menhaden fish meal (25%), soybean meal (35%, except in Diet 4), and shrimp meal (10%, except in Diet 4) as protein sources. Diet 1 had 0.5% lecithin added and 1.0% cholesterol added: Diet 2 contained 0% lecithin and 1.0% cholesterol; Diet 3 contained 0.5% lecithin and 0% cholesterol: and Diet 4 contained 0% lecithin and 0% cholesterol. After 8 wk, juvenile red claw fed diets with 0% supplemental lecithin (Diets 2 and 4) had no significant difference (P >0.05) in final weight and percentage weight gain (5.6 g and 2626%. respectively) compared to red claw fed the control diet (Diet 1) containing 0.5% lecithin. Red claw fed a diet without added cholesterol (Diet 3) had significantly (P 0.05) lower final weight (3.6 g) and percentage weight gain (1,717%) compared to red claw fed the control diet (Diet 1). However, red claw fed Diet 4 (containing 0% added cholesterol and 0% added lecithin) showed no significant (P >0.05) difference in final weight (5.1 g) and percentage weight gain (2254%) compared to red claw fed all other diets. There was no significant difference (P >0.05) among all diets for specific growth rate (SGR) which averaged 5.38%/d. Percentage survival was not significantly different among all treatments and was 76% for red claw fed Diet 1, 64% (Diet 2), 56% (Diet 3), and 80% (Diet 4). These results indicate that red claw fed Diet 4 containing 25% menhaden fish meal, 44.5% soybean meal, 0.5% choline chloride, 2% cod liver oil and 1% corn oil may satisfy the lecithin and cholesterol requirements and that the addition of dietary lecithin and cholesterol may not be necessary for good growth and survival of small (0.2 g) juvenile red claw. This may allow for less expensive diet formulations for use by producers of red claw crayfish.     

Should only females of giant freshwater prawn Macrobrachium rosenbergii be selected in genetic improvement programmes?

Sexual dimorphism is widely observed in almost all farmed aquatic animal species but giant freshwater pawn (GFP) is unique, with males characterized by three main morphotypes (blue claw, orange claw and small males) and females by different reproduction status (ovary, berried egg and already‐spawned females). There has been reported evidence that the effect of male morphotype may have masked genetic variation in growth‐related traits, as a result the heritability for male body weight was lower than that estimated in female. A pending question has arisen whether selection should be made in female only. To answer this question, we used an 8‐year data set from a long‐term selection programme (2008–2015) for high growth in this species comprising 106,756 individuals that were offspring of 515 sires and 810 dams. The body weight data of female and male GFP or of each morphotype was treated as a separate trait and a multi‐trait approach was used to estimate genetic correlations for homologous traits between sexes and between morphotypes. Our analysis showed that there were little differences in the heritability estimates between female and male. In female, mature ovary individual displayed higher heritability than berried egg and already‐spawned females. For male, the heritability for blue claw, orange claw and small males were 0.11, 0.06 and 0.00 respectively. Between‐sex genetic correlation was moderate (0.55 ± 0.11) for body weight, suggesting that the trait expressions in female and male may be genetically different. In female, the genetic correlations for body weight among three female types were close to one (0.91–0.94). In contrast, the genetic correlations for body weight between male morphotypes especially between blue claw or orange claw and small males were low (0.15–0.25). Furthermore, we estimated genetic gain as the difference in least square means (LSM) or estimated breeding values (EBV) between the selection line and control group. The genetic gain in body weight was smaller in females than in males. It is concluded that there is no need to run separate breeding programme for female and male GFP. A combined selection using both female and male data can achieve selection response for body weight as demonstrated in the present study.     

Forage-Based Feeding in Commercial Red Claw Ponds in Ecuador

Abstract

Red claw crayfish, Cherax quadricarinatus, are perhaps the first tropical species of crayfish to be cultured commercially. Culture traits and high market value could allow semi-intensive culture. Feeding strategies used in extensive crayfish ponds in temperate climates may not be the most appropriate for semi-intensive culture systems where year-round growth is possible. The following study was conducted to evaluate differences between using a pellet-based system versus a pellet-plus-forage-based system. The study was conducted in 14 0.3-ha ponds on a commercial farm in Ecuador. Juvenile red claw (1-2 g) were stocked into all ponds at a rate of 4/m². All ponds received pelleted shrimp rations at a rate of 3% per day. Seven ponds also received dried hay at a rate of 100 kg/ha/mo during the 3-month study. At harvest, red claw weights were similar (30-34 g), but survivals were significantly higher in ponds receiving pellets and hay (65%) than in ponds receiving pellets only (50%). Yields in pellet-fed ponds averaged 594 kg/ha, while red claw receiving pellets plus forage averaged 889 kg/ha. The addition of dried forage was thought to provide a larger variety of natural food organisms throughout a greater area of the pond bottom and provided additional substrate for dispersal and hiding. Addition of grasses from outside the pond is recommended over production of grasses grown within the pond.     

Effects of Added Substrate on the Production and Population Characteristics of Freshwater Prawns Macrobrachium rosenbergii in Ponds

The effects of added substrate on the growth and population characteristics of freshwater prawns raised in ponds were evaluated. Juvenile prawns (0.3 × 0.2 g) were stocked into six 0.04-ha ponds at a density of 59,280/ha. In three randomly selected ponds artificial substrate was added sufficient to increase available surface area approximately 20%. Three control ponds received no added substrate. Added substrate consisted of PVC frames with horizontal plastic mesh and vertical suspended seines. Prawns were fed a commercial diet (32% protein) twice daily according to a computer-generated feeding schedule. At harvest average individual weight, daily yield, and total yield were significantly higher (P < 0.05) in ponds with added substrate (37 g, 12.0 kg/ha per day, and 1,268 kg/ha, respectively). There was no significant difference in survival between treatments, averaging 59% overall. In ponds without substrate the number of small males (SM) was significantly higher and the number of orange claw males (OC) was significantly lower than in ponds with added substrate. Average individual weights of blue claw males, orange claw males, reproductive females, and virgin females were significantly higher (P × 0.05) in ponds with added substrate. Prawns raised in ponds containing added substrate had growth rates and population structures characteristic of prawns stocked at lower densities. Optimum relationships between stocking rates and amounts and types of added substrate should be evaluated as possible methods to increase production levels.     

Effects on growth,survival, body composition,processing traits and water quality when feeding a diet without vitamin and mineral supplements to Australian red claw crayfish (Cherax quadricarinatus) grown in ponds

To be profitable, producers must reduce diet costs, which can be as high as 80% of the variable costs of an aquaculture expense. As vitamin and mineral premixes represent a significant cost, eliminating addition of these premixes could reduce diet costs if no adverse effects were observed for growth and production parameters. A 105‐day feeding trial was conducted with juvenile Australian red claw crayfish (Cherax quadricarinatus) to evaluate the effects of growth, survival, body composition, processing traits and water quality when red claw were fed a supplemental diet containing 28% crude protein (CP) without vitamin and mineral premixes (and supplemented alfalfa hay) compared with red claw fed a diet (control diet) containing 42% CP, vitamin and mineral premixes, and with supplemented alfalfa hay, and compared with red claw only fed alfalfa hay when grown in ponds. Juvenile red claw (mean weight of 15.7 ± 1.0 g) were randomly stocked into nine 0.02‐ha ponds at a rate of 640 per pond (3.2 per m²), and each treatment was used in three ponds. There were two feedings per day, each consisting of one‐half of the total daily ration. At harvest, individual weight, percentage weight gain, specific growth rate, survival and total yield of red claw fed a control diet was significantly higher (P < 0.05) (83.0 g, 398%, 1.53% day^?1, 65.1%,and 1708 kg ha^?1 respectively) compared with red claw only fed alfalfa hay (44.9 g, 202%, 1.04% day^?1, 30.3% and 431 kg ha^?1, respectively), but not different (P > 0.05) from red claw fed the supplemental diet without vitamin and mineral premixes (76.2 g, 367%, 1.47% day^?1, 57.2% and 1378 kg ha^?1). There were no significant differences (P > 0.05) in feed conversion ratio (FCR) among treatments, which averaged 5.0 (based on prepared diet input). These results indicate that vitamin and mineral supplementation in a diet is not necessary when diet containing 28% CP and alfalfa hay are used in combination for pond grown red claw. These results may help reduce diet costs and possibly increase producers’ profits which might allow for industry expansion.     

不同脂肪源对红螯光壳螯虾幼虾生长、消化酶活性及其肌肉生化组成的影响

通过在人工配合饲料中分别添加5%的花生油、猪油、鱼油和豆油作为主要脂肪源,以商业饲料为对照,进行8周饲喂实验,研究不同脂肪源对红螯光壳螯虾(Cherax quadricarinatus)幼虾生长、消化酶活性及其肌肉生化组成的影响。结果显示,不同脂肪源对红螯光壳螯虾幼虾的体长增长率和特定增长率影响不显著(P0.05);但增重率各组间存在显著性差异(P0.05),以豆油组最高,达到2332.93%,花生油组最低,为1839.50%;豆油组肝胰腺指数显著高于其他各组(P0.05),为0.75%。幼虾存活率以豆油组最高(P0.05),达到83.3%,鱼油组较低,仅为56.7%。不同脂肪源饲喂组的肝胰腺胃蛋白酶活力无显著差异(P0.05);脂肪酶活力花生油组显著高于其他实验组(P0.05),为1177.23U/g(prot);淀粉酶活力各组间差异显著(P0.05),由高到低依次为鱼油组、对照组、豆油组、猪油组、花生油组;纤维素酶活力以花生油组较高,为61.14U/(gprot()P0.05)。幼虾腹部肌肉中各种脂肪酸的含量明显受到饲料中脂肪酸种类和含量的影响,饱和脂肪酸含量猪油组显著高于其他组(P0.05);单不饱和脂肪酸以花生油组含量最高,豆油组最低;多不饱和脂肪酸则以豆油组含量最高(P0.05)。在各实验组中,豆油组红螯光壳螯虾幼体具有最高的体质量增长率和存活率,较高的肝胰腺指数和肝胰腺消化酶活力,豆油组幼虾腹部肌肉中多不饱和脂肪酸尤其是亚油酸和亚麻酸含量也较高。因此,以豆油作为主要脂肪源能够满足红螯光壳螯虾幼体的生长需要,获得较好的饲养效果,并降低饲料成本。     

Replacement of the hip joint in the dog

Hundreds of total hip replacements in dogs have been performed at the Ohio State University of Veterinary Medicine since August 1976. Dogs with disabling diseases or conditions of the hip are candidates for the THR. The technique provides the dog with a pain free, mechanically sound ball and socket joint. The most commonly encountered complication is dislocation, while the most disastrous complication is infection. Complications can be minimized through adherence to detail during the procedure. By following strict aseptic principles, surgical technique and postoperative care, successful hip function has been achieved in 94.7% of the cases.     

Acclimation Procedures for the Australian Red Claw Crayfish,Cherax quadricarinatus

Abstract

Procedures to acclimate red claw crayfish, Cherax quadricarinatus, juveniles after transport times of 24 and 48 hours are described. Animals were kept in tanks and subjected to a purging process during 48 hours before shipping and packing. Acclimation tanks should have enough bottom area to avoid excessive aggregation of animals. Plastic onion bag nets added to the tank provide additional shelter for the juveniles. Oxygen levels should be maintained above 6 ppm and the temperature increased no more than 1 °C per hour. Using the described procedures, survival rates obtained 126 days after shipping and acclimation were 88.7% and 72.7% for the animals that had a transport time of 24 and 48 hours, respectively.     

Growth response and fatty acid composition of juvenile red claw crayfish (Cherax quadricarinatus) fed different sources of dietary lipid

A study was conducted to determine the effects of different sources of dietary lipid that differ in fatty acid (FA) composition on growth, feed conversion ratio (FCR), survival, and whole‐body proximate and FA composition of juvenile red claw. Juvenile red claw (0.55 ± 0.02 g) were reared over a 12‐week period. Five practical diets were supplemented with 70 g kg^?1 oil (by weight) from either linseed oil (LO), canola oil (CAO), corn oil (CO), beef tallow (BT) or menhaden oil (MO) and formulated to contain 400 g kg^?1 crude protein. Red claw were fed three times daily (800, 1200 and 1600) to controlled excess. At the conclusion of the experimental period, there were no significant differences (P > 0.05) found in percentage survival and FCR among dietary treatments and values averaged 85.4% and 3.4, respectively. However, final mean weight and specific growth rate of red claw fed Diet 1 (LO) was significantly higher (16.44 g and 3.95% day^?1, respectively) compared with that of red claw fed Diet 4 (BT; 12.24 g and 3.43% day^?1, respectively), but not different from red claw fed the other three diets. Likewise, red claw fed Diets 1 (LO) and 2 (CAO) had significantly higher percentage weight gain (2990 and 2880%, respectively) compared with the BT diet (2124%), but not different from red claw fed Diets 3 (CO) and 5 (MO). Whole‐body fat and ash composition was significantly affected (P < 0.05) by source of added lipid, but no differences were found in whole‐body moisture and protein. Moreover, whole‐body FA composition showed differences among the varying oil sources and primarily reflected the FA in the diets. Results of the present study indicate that plant oils LO, CAO and CO rich in linolenic acid (18:3n‐3), linoleic acid (18:2n‐6) and oleic acid (18:1n‐9) perform as well as MO containing high levels of n‐3 highly unsaturated fatty acids eicosapentanoic acid (20:5n‐3) and docosahexaenoic acid (22:6n‐3) for juvenile red claw crayfish grown indoors lacking natural food items. Further, red claw fed a diet containing BT, which has a high percentage of saturated FA, performed poorly compared with LO and CO in regards to weight gain. It appears that juvenile red claw can be fed diets containing less expensive plant‐based oils with high levels of 18‐carbon unsaturated fatty acids. This could reduce diet costs for producers and allow for profitability.     

Lecithin requirements of juvenile Australian red claw crayfish Cherax quadricarinatus

Australian red claw crayfish Cherax quadricarinatus is considered a popular crustacean species in several countries around the world because of its large size potential and resemblance to high‐priced American lobsters. However, little is currently known of the nutrient requirements and practical diet formulations for red claw. Lecithin has been shown to be required in the diets of several crustacean species, but there are no reports of dietary lecithin requirements for red claw. A 10‐week feeding trial was conducted in an effort to evaluate lecithin requirements for juvenile red claw. Juvenile red claw (mean individual weight of 1.6 ± 0.91 g) were individually stocked in a recirculating system at random into 80 plastic‐mesh culture units, each containing its own individual water line. There were 20 red claw per treatment (diet). Water was recirculated through biological and mechanical filters. Four semi‐purified diets were formulated to contain increasing percentages of commercial soya bean lecithin (0, 0.5, 1.0 and 2.0%). Diet ingredients included solvent‐extracted menhaden fish meal (FM), casein, dextrin, wheat flour, pellet binder, vitamin and mineral mix, cod liver oil, and corn oil. Semi‐purified diets were formulated to contain 40% protein using casein, menhaden FM, and wheat flour as protein sources. After 10 weeks, no significant differences (P > 0.05) were found in final weight, percentage weight gain and specific growth rate with average values of 13.0 g, 934%, and 3.14% day^?1, respectively. Percentage survival was high during the 10‐week period (100, 95, 100 and 95%) as only two individuals died during the study; one of these, because of an escape from the culture unit. There was also no significant differences (P > 0.05) in percentage moisture, protein, fat and ash in whole‐body red claw carcasses (wet‐weight basis) among any treatment (diet) and averaged 77.1, 12.6, 1.3 and 6.2%, respectively. Based upon the present study, these results indicate that a diet containing 5% cod liver oil and 1% corn oil, and having no supplemental lecithin, may be sufficient for growth and survival of juvenile red claw crayfish.     

Effects of feeding practical diets containing various protein levels on growth, survival, body composition, and processing traits of Australian red claw crayfish (Cherax quadricarinatus) and on pond water quality

A 117‐day feeding trial was conducted in ponds with juvenile Australian red claw crayfish (Cherax quadricarinatus) to evaluate the effects on growth, survival, body composition, and processing traits when fed diets containing three different protein levels (22%, 32%, and 42%), and the effects of feeding these diets on pond water quality. Juvenile crayfish (mean weight of 4.6±2.2 g) were randomly stocked into nine 0.02‐ha ponds at a rate of 500 per pond (25 000 ha^?1), and each diet was fed to three ponds. There were two feedings per day, each consisting of one‐half of the total daily ration. At harvest, there were no significant differences (P>0.05) in the individual weight, percentage weight gain, or specific growth rate among treatments, which averaged 75.3 g, 1535%, and 2.38% day^?1 respectively. Red claw fed the 42% crude protein diet had significantly higher (P<0.05) feed conversion ratio (7.34) compared with crayfish fed diets containing 22% (5.18) or 32% (5.13) crude protein, and had significantly lower percentage survival (46.1%) compared with red claw fed diets with 22% (61.1%) or 32% (58.2%) protein. Total yield was significantly lower (P<0.05) in red claw fed the 42% protein diet (640 kg ha^?1) compared with red claw fed diets containing 22% (920 kg ha^?1) or 32% (904 kg ha^?1) protein. Mean total ammonia nitrogen (TAN) levels were significantly higher (P<0.05) in ponds with red claw fed the 42% protein diet (0.55 mg L^?1) compared with ponds with red claw fed diets containing 22% (0.32 mg L^?1) or 32% (0.38 mg L^?1) protein. Mean total nitrite concentrations in ponds with red claw fed the 42% protein diet was significantly higher (0.05 mg L^?1) compared with red claw fed diets containing 22% (0.01 mg L^?1) or 32% (0.02 mg L^?1) protein. These results indicate that a practical diet containing 22% (as fed basis) protein may be adequate for pond production of red claw when stocked at the density used in this study, and that a diet containing 42% protein adversely affected levels of TAN and nitrite, possibly reducing overall survival of red claw. Use of a diet with 22% protein may allow red claw producers to reduce diet costs and thereby increase profits.