Commercial assessment of growth and mortality of fifth-generation Sydney rock oysters Saccostrea glomerata (Gould, 1850) selectively bred for faster growth

The Sydney rock oyster Saccostrea glomerata (Gould, 1850) industry acquired hatchery-produced spat selected for faster growth for the first time in January 2004. Selectively bred and non-selected (Control) spat produced concurrently were used to compare performance when grown under commercial conditions. Spat were distributed to farmers in seven estuaries in New South Wales. Individual farmers cultivated these oysters using their own techniques and growth and mortality were recorded quarterly. At each site, the two oyster types were cultivated using the same culture method, location and density. Growth was compared when oysters were 27 months of age. At this time, selectively bred oysters were significantly larger and heavier than Control oysters. The same result was obtained when oysters were compared at the point in time when selectively bred oysters had reached 50 g at each site. No significant difference was found for cumulative mortality between the selectively bred oysters and Control oysters across all sites. However, the seven sites had significantly different levels of cumulative mortality. Overall, the performance of selectively bred oysters was superior to the Control oysters and selectively bred oysters reached the 50 g bench mark within 29.3 months when averaged across all sites.     

Amino acid availability and protein digestibility of several protein sources for Nile tilapia,Oreochromis niloticus

Apparent amino acid availability coefficients and protein digestibility of four animal products [fish meal (FM), meat and bone meal (MBM), poultry by‐product and feather meal] and four plant protein‐rich products [soybean meal (SBM), cottonseed meal‐28, cottonseed meal‐38 and corn gluten meal (CGM)] were determined for Nile tilapia, Oreochromis niloticus. Ingredients were incorporated to a practical reference diet at a 7 : 3 ratio (70% of reference diet and 30% of test ingredient). Chromic oxide was used as external digestibility marker. Among animal products poultry by‐product meal (PBM; 89.7%) and FM (88.6%) presented the highest apparent protein digestibility (APD) while MBM (78.4%) and feather meal (78.5%) presented the lowest APD. Among plant protein‐rich products CGM (91.4%) and SBM (92.4%) presented the highest APD values while cottonseed meal‐28 presented the lowest APD (78.6%). Average apparent amino acid availability of feed ingredients was similar to protein digestibility with 92.3%, 89.6%, 73.4%, 80.7%, 88.9%, 84.4%, 91.2% and 79.7% values for SBM, CGM, cottonseed meal‐28 and 38, FM, MBM, PBM and feather meal respectively. These results indicate that O. niloticus is able to utilize efficiently different feedstuffs.     

Hematologic disorders of fish

Hematology can be a useful tool for monitoring health status, detecting illness, and following the progress of disease and response to therapy. Despite advances in fish medicine in recent years, interpretation of fish hematology often is hampered by a lack of meaningful reference values and the bewildering diversity of fish species. A multitude of intrinsic and extrinsic factors cause normal and abnormal variation in hematologic data. This article provides an overview of some of the hematologic abnormalities in fish induced by infectious agents and environmental, husbandry, and nutritional issues.     

Simultaneous cecostomy and ileal cannulation with a modified flexible T cannula in gilts

A surgical procedure was developed for the simultaneous cannulation of the ileum and fistulation of the cecum in breeding-age gilts to study the effects of enteric microflora on the nutritional requirements and/or status of the pig. Flexible T-shaped cannulae were made from plastic tubing, placed surgically in the caudal part of the ileum, and exteriorized in the right paralumbar fossa. After the exteriorization of the cecal apex in the right flank area, a cecal fistual was made caudoventral to the ileal cannula. Prececocolonic contents could be collected from the ileal cannulae and/or substances could be infused into the cecum. The flexible cannulae were light weight (35 g), were easily replaced when dislodged with minimal tissue trauma and minimal discomfort to the animal, and had good animal tolerance and patency in long-term experiments. The cecal fistulae allowed the direct introduction of various substances into the cecum. There was little external projection from the abdominal wall, and the fistulae were subject to minimal leakage. The procedure did not adversely affect the subsequent health or performance of the 43 gilts used in the experiment. Postmortem examination of gilts euthanatized 12 to 26 weeks postoperatively revealed normal tissue adhesions around the surgical sites with no detrimental effects on the gastrointestinal tract.     

The effect of copper addition to diets with various iron levels on the performance and hematology of weanling swine

A 2 x 6 factorial experiment with Cu added at 5 or 250 ppm and Fe added at 50, 100, 150, 200, 250, or 300 ppm was conducted using 480 crossbred weanling pigs with an average initial weight of 7.0 kg. The basal corn-soybean meal-whey diet contained 4 ppm Cu, 169 ppm Fe, and 199 ppm Zn. Pigs were allotted by weight, sex, and litter outcome group and had ad libitum access to feed and water during the 28-d trials. Animals were weighed and pen feed intake was recorded weekly. Blood samples were collected on d 1, 14, and 28 of the experiment. The addition of 250 ppm Cu increased ADG (P less than .001) and average daily feed intake (ADFI, P less than .01) during the 28-d trials. The addition of Fe had no effect on ADG and ADFI (P greater than .10). A Cu x Fe interaction (P less than .01) was observed for feed/gain. Increasing Fe levels linearly improved hematocrit status (P less than .05) on d 28 of the trial. A Cu x Fe interaction (P less than .08) was observed for hemoglobin at the end of the trial; hemoglobin levels were increased by the addition of Fe to the diet containing 250 ppm of Cu. Plasma Cu was increased (P less than .001) by the addition of 250 ppm of Cu. Plasma Fe was low when either 50 or 100 ppm of Fe was added in the presence of 250 ppm of Cu, but it was not affected at other levels, resulting in a Cu x Fe interaction (P less than .05). These data indicate that levels of added Fe up to 300 ppm may help to improve the hematological status of weanling pigs fed growth-promoting levels of Cu but that it has little effect on performance.     

Effect of vitamin E and copper on the vitamin E status and performance of growing pigs

A 13-wk trial was conducted with 32 pigs to determine the effects of dietary Cu (250 ppm) and alpha-tocopheryl acetate (ATA, 22 IU/kg) on the performance, serum enzymes, serum and tissue tocopherols, and antibody production in growing pigs. Pigs were fed corn-soybean meal diets containing 21% CP the first 4 wk and 18% CP during the rest of the trial. All feed was stored a minimum of 14 d before it was fed. The addition of Cu decreased (P less than .01) the concentration of alpha-tocopherol in the feed. alpha-Tocopherol concentrations were less than .01 mg/kg in the starter diet and less than 2 mg/kg in the grower diet after 14 d of storage. Supplemental Cu or ATA had no effect on ADG, feed intake, or gain:feed during the first 4 wk. During wk 5 to 13, the addition of Cu to diets containing no ATA increased daily feed intake and decreased gain:feed, but with ATA addition, feed intake decreased and gain:feed increased, resulting in a Cu x ATA interaction (P less than .05). The addition of Cu or ATA had no effect (P greater than .1) on serum glutathione peroxidase or lactic dehydrogenase activity. Serum tocopherols were reduced (P less than .05) by the addition of Cu during wk 1 to 4, 6 (P less than .01), and 7 (P less than .05) and increased (P less than .01) by ATA addition during the entire experiment. The addition of ATA increased the tocopherol concentrations in bile, ham, heart, pancreas, kidney, spleen, liver, psoas and longissimus muscle (P less than .01), kidney fat, backfat, and adrenal gland (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Responsiveness to Progestagen-eCG-Cloprostenol Treatment in Goat Food Restricted for Long Period and Refed

For 6 months, 10 adult Saanen crossbred goats were fed undernutrition diet (70% maintenance), and finally five goats were refed for 6 weeks with 150% maintenance. In all animals oestrus was synchronized using 45 mg FGA vaginal sponge for 11 days, 300 IU eCG and 50 microg cloprostenol 48 h prior to sponge removal. From oestrus onset, during a 24-h period, blood samples were collected for oestradiol and NEFA assay. Ovulation was verified by laparoscopy 3 days after sponge removal. Body mass loss was 18.62 +/- 3.03% of initial weight and in refed goats body weight recovery was 90.63 +/- 3.56%. NEFA level was higher in restricted goats (p < 0.05). Fifty per cent of underfed goats (2/4) and all refed goats (4/4) exhibited oestrus and ovulation. Significant relationship (p < 0.05) was found between weight loss and the interval sponge removal-oestrus onset (r = 0.91) or ovulation rate (r = 0.70). Only in the refed group was the ovulation rate related to the oestradiol amount (r = 0.99) (p < 0.05). Collectively results showed that a short period of improved feeding re-established the responsiveness of oestrus synchronization in chronically fasted goats.