Ultrastructure of the tubular glands in the isthmus region of the oviduct in laying and natural moulting commercial egg‐type chickens

The study investigated the ultrastructural characteristics of tubular gland and duct cells, as well as luminal gland cells in the isthmus region of the oviduct of laying and natural moulting hens. Tubular glands in laying birds were composed of type 1 and 2 cells. Based on the preponderance of each cell type, in relation to the location of a developing egg in the oviduct of the domestic fowl, these gland cells may represent different functional states of the same cell. The findings of the study on natural moulting birds suggest that autophagy is a process confined to the early stages of degeneration, while necrosis occurs in the terminal stages.     

细指长臂虾的幼体发育

1991年4月，从长江口采回细指长臂虾抱卵亲虾，至实验室进行幼体培育。孵化后的幼体，在水温22℃．盐度12、饵料充足的条件下，有规律的每2d蜕皮1次，经10个状幼体期，变态为仔虾。如在发育后期遇饵料不足等不良环境条件的影响，则幼体须经11次蜕皮后，始能发育为仔虾。     

罗氏沼虾繁殖习性的研究

本文对罗氏沼虾的繁殖习性进行了较为详细地描述。性成熟的雌虾必须经过生殖蜕皮方可交配、产卵；受精卵粘附于腹肢刚毛上；在水温２４℃左右的条件下，幼体孵出约需２７天；性成熟雌虾能多次产卵。     

中华绒螯蟹蜕皮过程中肌肉、肝胰脏和甲壳中钙和磷含量的变动

对中华绒螯蟹蜕皮间期和蜕皮后24h、48h和96h肌肉、肝胰脏及甲壳中钙和磷的含量进行了测定。蜕皮后肌肉中钙的含量较间期低，但从24h到48h有所增加。肝胰脏中钙的含量在蜕皮后各时间内无显著变化，甲壳中钙的含量在蜕皮后24h到96h呈增加趋势。甲壳的矿化作用在蜕皮后96h已接近完成。蜕皮后肌肉中磷的含量较间期高，以后变化不明显。蜕皮后肝胰脏中磷的含量高于间期，甲壳中含量较间期低。蜕皮后肌肉中钙磷比迅速降低，肝胰脏中钙磷比在蜕皮后24h无明显变化，但在蜕皮后24h至96h迅速降低。中华绒螯蟹蜕皮后外表皮对钙的矿化速度显著快于磷的矿化速度。     

The release and uptake of metals from potential biofilm inhibition products during spiny lobster (Sagmariasus verreauxi,H. Milne Edwards 1851) culture

Zinc (Zn) and copper (Cu) are strong inhibitors of bacterial biofilms in aqueous solutions, but are known toxins of crustaceans. A new metal application method; cold‐sprayed metal embedment, known to modulate metal release, was tested for its applications in crustacean larval culture systems. Cold‐spray technology allows metal particles to bond to plastics, while modulating metal ion release and biocide activity to the substrate boundary. In this study, Eastern spiny lobster (Sagmariasus verreauxi) larvae (phyllosoma) were cultured in the presence of cold‐sprayed Zn and Cu metal surfaces. Metal loss was monitored gravimetrically on embedded surfaces, assessment of water ion concentrations and analysis of phyllosoma body content were undertaken. Phyllosoma moulting, deformity and mortality patterns were monitored. Cold‐sprayed Zn‐ and Cu‐embedded surfaces were depleted with losses of 0.69% and 31.2% noted respectively. Culture water concentrations of these metals were elevated and accumulation by phyllosoma occurred. Water Zn concentrations of 18.5 μg L^?1 were associated with chronic eyestalk moult deformities; the first report of Zn causing a non‐lethal moult deformity in crustacean larvae. The Cu surface lost a third of its metal mass with a water concentration of 40 μg L^?1 causing acute toxicity and localization of composite granules in the midgut gland. Cu associated mortality was noted by Day 2 of culture with a LD 50 experienced by Day 9. Future work on the use of bioactive metals in aquaculture systems will focus on a range of different metal alloys, and improved modulation of ion release mechanisms through increased particle embedment depth and separation.     

Sterols that modify moulting in insects

The development of insects is under the control of a steroid hormone, ecdysone. This paper reviews suicide substrate type inactivators designed to inhibit the biosynthesis of ecdysone. Several series of acetylenic derivatives of cholesterol were synthesized and their biological effects on the prothoracic glands of the locust were investigated in vitro, enabling structure-activity relationships to be studied. Information on the ability of brassinosteroids, a series of plant growth regulators, to inhibit ecdysteroid activities of insects is discussed as a precursor to a study of brassinosteroid ecdysone mimics.     

Stepwise function of natural growth for Scylla serrata in East Africa: a valuable tool for assessing growth of mud crabs in aquaculture

Predicting growth is critical in aquaculture, but models of growth are largely missing for mud crab species. Here, we present the first model of natural growth in juvenile and adult mud crabs Scylla serrata from East Africa using a stepwise growth function based on data on intermoult periods and growth at moult from field mark‐recapture, pond and laboratory studies. The results showed a sigmoid growth pattern in carapace width and suggest that S. serrata in East Africa will reach 300 g and sexual maturity ~9.9 months after settlement, and a commercial size of 500 g after 12.4 months. Analyses of the literature identified several issues with the common praxis to compare standard growth measures between aquaculture studies with different initial size or growing periods. Using the new growth function to estimate the proportional difference between modelled and obtained growth as an alternative method, we show that growth rates of S. serrata cultured in cage systems, which are dominant in East Africa, was <40% of the estimated natural growth and growth obtained in pond systems. The analysis also indicated that growth rates of S. serrata in Southeast Asia was over 50% higher compared with similar culture systems in East Africa, and that different species of mud crabs had large differences in growth rates. This study shows that growth in the present mud crab aquaculture systems in East Africa is below their expected potential. Further work is needed to identify the factors behind this observation.     

Identification of SNPs in the 5′‐flanking region and 3′‐UTR of the MIH gene and their association with precocity of the Chinese mitten crab Eriocheir sinensis

Moult‐inhibiting hormone (MIH), an important regulator of steroidogenesis, inhibits the synthesis of ecdysteroid in Y‐organ (YO) and plays a significant role in the regulation of moulting and post‐embryonic development of crustacean. Because unsuccessful moulting have been widely observed in precocious crabs, we investigated whether genetic variants in the 5′‐flanking region and 3′‐untranslated region (3′‐UTR) of the MIH gene are associated with precocity of the Chinese mitten crab. Thirty individual DNA samples were sequenced to search for SNPs in the 5′‐flanking region and 3′‐UTR of the MIH gene. Five SNPs (g.196 T>A, g.230 C>T, g.305 T>C, g.323 C>A and g.372 C>T) in the 5′‐flanking region and 6 SNPs (g.2677 C>T, g.2759 T>A, g.2807 T>C, g.3042 A>G, g.3088 T>G and g.3295 T>G) in the 3′‐UTR of the MIH gene were selected for the individual genotyping in a two‐stage association study. We found that a SNP g.3088 T>G in the 3′‐UTR of MIH gene was consistently associated with precocity of the Chinese mitten crab in stage 1 and stage 2, with a per‐allele OR (Odds Ratio) of 1.469 (95% CI: 1.169–1.844) after two stages combined (P = 0.001). However, no significant associations were observed between the other 10 SNPs and precocity of the Chinese mitten crab. To our best knowledge, this is the first association study between various SNP genotypes and phenotype attributes in Chinese mitten crab. Our findings suggest that the SNP g.3088 T>G may be a candidate marker for effective marker‐assisted selection to decrease the precocity of the Chinese mitten crab in future studies.     

Evaluating the impact of moulting and chilled storage of spermatophores on the integrity of plasma membrane,acrosome and DNA of black tiger prawn (Penaeus monodon) spermatozoa

To explore the impact of moulting and short‐term chilled storage of spermatophores on the sperm quality for a commercially important penaeid prawn, spermatozoa of Penaeus monodon from early (B‐C), middle (D0‐1) and late (D2‐3) moult stages were compared for sperm quality parameters relating to the structural integrity of plasma membrane (Viab%), acrosome (AR%) and DNA (SDF%) after being stored at 4°C for 0–26 days. The three different sperm extenders used for chilled storage included artificial lobster haemolymph (AH), calcium free saline (CS) and filtered seawater (FS); two storage conditions were applied either as a free sperm suspension or retained within the intact spermatophore. Results showed that (a) the lowest natural AR% was shown for B‐C spermatozoa in CS whereas the highest levels were for B‐C, D0‐1 and D2‐3 spermatozoa in FS and D2‐3 spermatozoa in AH; (b) the calcium ionophore A23187 agent used in this study was able to increase the mean AR% by 6.22%; (c) the Viab% was significantly lower in CS than that in FS; (d) the SDF% significantly increased over the period of chilled storage for B‐C and D0‐1 spermatozoa, while the SDF% of D2‐3 spermatozoa was initially elevated and did not change significantly over time; and (e) there was no difference in sperm quality between two storage conditions. This study has successfully demonstrated the moult‐related variance in the percentages of acrosome‐reacted and DNA‐damaged spermatozoa, providing evidence of moult‐related spermatophore renewal cycle in this species.     

An appraisal of moulting on post-moult egg production and egg weight distribution in white layer hens; meta-analysis

1. The aim of this study was to establish how different moulting methods and body weight losses influenced post-moult performance and USDA egg weight distribution.

2. Data on 5 laying flocks (#34–38) of the North Carolina Layer Performance and Management Test were used in this meta-analysis.

3. The moulting methods were non-fasted moulted (NF), short feed restricted (SF), 13-d feed restricted (FR), non-anorexic moult programme (NA), non-anorexic moult programme with low sodium (NALS) as well as non-moulting programme as control treatment. The percentages of targeted body weight loss during the moulting period were 20, 24, 25 and 30% of body weight at the end of the first egg production cycle.

4. Post-moult egg production and egg mass were influenced by all moulting methods. Maximum increase in post-moult egg production rate and egg mass occurred with FR and NF programmes, respectively, at 30% of body weight loss, compared to non-moulted hens. Non-fasting methods reduced mortality rate more effectively than fasting methods.

5. Moulting resulted in increases in percentage of grade A and decreases in percentage of grade B eggs. Non-fasting methods increased percentage of grade A eggs more effectively than fasting methods. Percentage of cracked eggs decreased in moulted rather than non-moulted hens and the lowest rate was associated with the NA programme.

6. Post-moult egg weight was not significantly influenced by moulting methods. However, percentage of body weight reduction affected egg weight. The optimum increment in egg weight was achieved by 24% body weight reduction.

7. Overall, non-fasting methods resulted in similar egg production compared with fasting methods. Considering post-moult mortality and USDA egg weight distribution, non-fasting methods, especially NF and NA programmes, performed much better than fasting methods, indicating that non-fasting moulting methods, which are better for animal welfare, are effective alternatives to fasting methods.