Notes on the diet of Pterogymnus laniarius (Cuvier) (Pisces: Sparidae)

Stomach contents of fish taken between Mossel Bay and Algoa Bay were analysed. Prey associated with both hard and soft substrates were present in the diet although the latter were more Important. The mouth structure Is shown to be well adapted to feeding over soft substrates.     

Age,Growth and Aspects of Reproduction of the Mackerel Scomber Japonicus in South African Waters (Pisces: Scombridae)

The age and growth of the mackerel were determined from 1742 otoliths collected from commercial catches. The time of annulus formation was established from otolith edge examinations. Two zones. one opaque and one hyaline, are laid down during a year. The distance of each annulus from the nucleus of the otolith was measured. Mean measurements were substituted in a linear regression equation which describes the relationship between otolith radius and fish length to obtain back-calculated length at age values. Growth in length and in mass are expressed by the von Bertalanffy growth equation. Length and age at first maturity were established by macroscopic examination of mackerel gonads. All mackerel were found to mature during their fourth year of life, at 42 cm standard body length. Spawning takes place during the period June to September.     

Ecology,Osmoregulation and Reproductive Biology of the White Steenbras,Lithognathus Lithognathus (Teleostei: Sparidae)

Over a one-year period 437 steenbras, Lithognathus lithognathus, ranging from 8-39 cm fork length were sampled from the Heuningnes River Estuary. The length-weight relationship was linear and there was no fluctuation in the modal size range throughout the year. Steenbras up to the age of six years and over inhabited the estuary, adapting to large salinity fluctuations. Abundance of food items, mainly Crustacea and Annelida, and virtual absence of predators made the estuary an ideal nursery ground. Ectoparasitic infestation by leeches and copepods was moderately intense without causing any apparent deleterious effects.

In a series of experiments designed to study osmoregulation in steenbras, it was found that haematocrits from fish sampled after 48 hours in freshwater were significantly (P<0,01) higher than the seawater controls. Two of the five protein fractions, however, as well as total protein, chloride, sodium, potassium and osmolality were all significantly (P<0,01) decreased in freshwater. Steenbras were unable to survive more than one week in freshwater. Due to capture diuresis the plasma constituents from a freshly captured sample were all significantly (P<0,01) higher when compared to steenbras acclimated for 48 hours in seawater.

Gonads from the entire estuarine sample were all infantile, virtually impossible to sex and showed no macroscopic signs of development. Histology of a representative sample showed them to be all hermaphroditic, with mainly testicular-dominant ovotestes. Maturity indexes assigned on the basis of ovarian and testicular development gave an indication of a cyclic rhythm in activity during pre-maturation, with a June peak. Marine steenbras ovotestes, on the other hand, were large and could be accurately sexed macroscopically. Histology of 42 gonads again revealed a majority of testicular-dominant hermaphroditic ovotestes. Maturity indexes indicated peak activity in June and a minimum in September, suggesting a spawning period in July and August.

Sex-chromatin (Barr) bodies were detected in liver nuclei of ovarian-dominant ovotestes, but were almost entirely absent from testicular-dominant ovotestes. Prediction of the genetic sex against the actual dominant macroscopic sex, based on the presence or absence of Barr bodies in a sample of steenbras liver sections proved very accurate. This is the first record of sex-chromatin occurring in teleost tissue.

There was no indication of sex-reversal, the steenbras remaining permanently hermaphroditic throughout the study year. It is postulated that the steenbras is a rudimentary hermaphrodite with only one of the two sexes functioning throughout the individual's life span. This is possibly a transitionary stage towards eventual gonochorism.     

Distribution and reproduction of the reef fish Petrus rupestris (Pisces: Sparidae) off the coast of South Africa

The red steenbras (Petrus rupestris) is endemic to the south and south-east coasts of South Africa and is the largest member of the family Sparidae. Morphometric relationships between length and mass are given for whole and eviscerated fish. The size distribution of P. rupestris is related to locality and water depth. Juveniles and sub-adults are common in shallow (< 50 m) Cape waters between False Bay and East London. Adults are more common offshore, in deep waters (> 50 m), especially off the coast between East London and Coffee Bay, throughout the year. P. rupestris were found to be rudimentary hermaphrodites. The development of the functional sexes, and the occurrence of sexual dichromatism, are described. Sexual maturity is attained at about 575 mm fork length in those fishes in the spawning areas. Reproductively ripe fishes were taken from Transkei, East London and a small collection was made from the Agulhas Bank. Peak spawning is between August and October. Current management regulations are discussed and advantages of large marine reserves in conservation of this mobile apex predator are outlined.     

马来穿山甲的年龄结构及寄生物

以广东湛江市林业公安局没收的51头马来穿山甲活体标本为材料,分析研究其年龄结构和寄生物。根据鳞甲、毛发、爪的磨损程度以及母幼行为关系和体重大小,将马来穿山甲划分成4个年龄组:幼年组、亚成年组、成年组和老年组,分别由7(13.7%)、21(41.2%)、19(37.3%)和4头(7.8%)个体组成,性比(♀∶♂)为1∶0.97。通过体表观察、粪检和解剖观察,发现被蜱感染过的穿山甲体况下降,且这些穿山甲仅有1种体外寄生物,为爪哇花蜱(AmblyommajavaneseSupino,1897),感染率为68.63%(35/51),未见幼体被感染。同时还讨论了该物种野放的生态安全问题。     

Notes on the biology of juvenile Sparodon durbanensis (Pisces: Sparidae) from tidal pools in the Eastern Cape,South Africa

The length/frequency distribution, length/mass relationship, seasonal occurrence, growth and diet of Sparodon durbanensis from tidal pools in the Eastern Cape was investigated over a two-year period. The fish were predominantly small (mean length of 53 mm TL) with the smallest specimens being found in summer. Juveniles were found to be omnivorous, consuming algae, crustaceans and polychaetes, although, with the acquisition of adult dentition (ie. crushing molars), hard-shelled molluscs became important in the diet.     

Age,growth and food of Cheimerius nufar (Ehrenberg, 1820) (Sparidae), collected off St Croix Island,Algoa Bay

Age and growth of the santer, Cheimerius nufar, were determined from otoliths. One hyaline and one opaque ring are laid down yearly. The von Bertalanffy growth function yielded the equation L_t = 953,56 [1-e^-654(t ^{+ 2,6177})]. The length-mass relationship W = 0,00005 L^2,7831 was used to determine growth in mass: W_t = 9790,24 [1-e^{-0,0654(t+2,6177)}]^2,7831. Stomach and intestine content analyses were done, using a modification of the points method, as well as the frequency of occurrence method. C. nufar is primarily a piscivore, but also preys on cephalopods and crustaceans.     

Diet composition and breeding cycle of blacktail,Diplodus sargus capensis (Pisces: Sparidae), caught off St Croix Island,Algoa Bay,South Africa

The contents of the alimentary tracts of D. sargus capensis were analysed to establish diet composition. The importance of analysing stomach, intestine and total alimentary tract, separately, is emphasized. D. sargus capensis is an omnivore preying on lower intertidal and shallow subtidal benthic species. Cirripedia and algae were the most important groups and constitute ca. 60% of the total dietary composition. Ulva sp., Perna perna and Balanu, spp. were prefered species. A new index for ranking prey items, which combines the modified points method and the frequency of occurrence method, is suggested. It is especially useful for omnivorous fish where prey items sucl as seaweed and colonial organisms are difficult to enumerate. Ambosexual individuals differentiate into functional males or functional females. Active spermatogenesis in the ovo-testis suggests a special type of protandric development. D. sargus capensis has an extended breeding cycle with a peak spawning period from October to December.     

A Comparison of the Otolith and Scale Methods of Ageing,and the Growth of Sarotherodon Mossambicus (Pisces: Cichlidae) in a Venda Impoundment (Southern Africa)

Otoliths and scales were used for age and growth determinations of Sarotherodon mossambicus In the Luphephe-Nwanedzi impoundment, a subtropical man-made reservoir in Venda, northern South Africa. Two rings are deposited annually on the otolith whereas only one ring Is deposited on the scales. Using otoliths the growth of S. mossambicus is described by L_t = 27,3 (1 - e^{-0,425(t + 0,299)})cm and using scales by L_t = 26,8 (1 - e^{-0,389(t + 0,045)}) _cm. These two curves differ significantly (P<0,01). The adequacy of these curves was tested by means of Ford-Walford plots. It is postulated that otoliths provide a more reliable estimate of age and growth than scales in subtropical and temperate regions. Males grow faster than females. Based on otoliths the growth of male S. mossambicus in the Luphephe-Nwanedzi impoundment is described by L_t = 27,0(1 - e^{-0,417(t + 0,504)}) cm SL and that of females by L_t = 25,8(1 - e^{- 0,370(t + 0,497)}) cm SL. The growth of S. mossambicus in the Luphephe-Nwanedzi impoundment is compared to other S. mossambicus populations in South Africa.     

The diet,food selectivity and niche of Rhabdosargus sarba (Teleostei: Sparidae) in Natal estuaries

The juveniles and subadults of Rhabdosargus sarba are one of the most common components of the benthic fish community of Natal estuaries. The diet consists mainly of aquatic macrophytes and filamentous algae although a significant proportion is made up of bivalves and the amphipod Grandidierella lignorum. The last two taxa are positively selected when little plant material is consumed. R. sarba feeds during daylight with a peak in the early afternoon. The relationship between R. sarba and the very similar sympatric R. holubi and R. auriventris are discussed in relation to their diet, divergence and distribution. Resource partitioning in Natal estuaries between R. sarba, the Gerreidae and Pomadasys commersonii is also discussed.     

不同抗生素对红色型豌豆蚜生长发育和繁殖的影响

为明确不同抗生素处理方式对红色型豌豆蚜(Acyrthosiphon piusm)生长发育和繁殖的影响,将利福平、盐酸金霉素、氯霉素、盐酸土霉素、青霉素G 钾盐和硫酸链霉素6种抗生素分别进行同时喷洒蚕豆(Vicia faba)植株和蚜虫虫体、只喷洒蚜虫虫体和只喷洒蚕豆植株3种处理,获得了各处理下红色型豌豆蚜发育历期和平均产蚜量生物学参数.结果表明:对其生长发育和繁殖影响最大的抗生素是利福平;影响最大的处理方式是同时喷洒植株和虫体.4种组合处理影响大小顺序为:利福平同时喷洒植株和虫体处理>利福平喷洒植株处理>利福平喷洒虫体处理>土霉素同时喷洒植株和虫体.     

Early development and larval behaviour of a minnow,Barbus anoplus (Pisces: Cyprinidae)

The chubbyhead barb, Barbus anoplus, underwent a population explosion in the early phases of filling of Lake be Roux on the Orange River. This successful colonization was possibly related to the survival strategy of the young stages of this minnow. It is suggested that some of the development traits of B. anoplus enabled it to become the most widespread freshwater fish species south of the Limpopo River. The development and behaviour of embryos and larvae of B. anoplus are described and discussed with reference to their survival strategy and potential colonizing ability. Some of the protolarvae were pelagic and the relevance of this behaviour is noted.     

儿茶酚、香豆素对豌豆蚜生长发育及繁殖的影响

儿茶酚、香豆素是植物的次生代谢物质对桃蚜等有拒食功能,但是对豌豆蚜的作用尚未见报道。为了明确儿茶酚、香豆素对红、绿色型豌豆蚜（Acyrthosiphon pisum）生理的影响。本研究采用人工饲料喂养技术测定了豌豆蚜的生理指标。结果表明：随着两种物质浓度的增加,两种色型蚜虫的存活率、繁殖率都在显著下降,但在相对日均体重增长率之间差异不明显。香豆素对红色型的繁殖率影响比对绿色型的更加明显。红色型在60 mg·L^-1处理时已经为零,而绿色型在100 mg·L^-1时依然有繁殖。红色型的存活率、产蚜率、平均产蚜量比绿色型的更容易受到儿茶酚的影响,在儿茶酚浓度最高时红色型的存活率在时间顺序上分别是73.30±1.50%,20.00±0.00%,0.00±0.00%,绿色型的为66.60±0.80%,26.7±2.00%,3.30±0.10%。而在儿茶酚浓度最低时红色型的平均产蚜量、产蚜率为3.70%±0.80%,16.70±0.60%,绿色型为9.00±0.60%,30.0±0.70%。这说明绿色型比红色型对香豆素、儿茶酚的耐受性更好。     

Prevalence of the Proventricular Nematode Tetrameres americana Cram (1927) in Different Age Groups of Chickens in the Morogoro Region,Tanzania

Tropical Animal Health and Production -     

单宁酸对红、绿色型豌豆蚜生长发育及繁殖的影响

为明确单宁酸对两种色型豌豆蚜生长发育及繁殖的影响,本研究采用豌豆蚜全纯人工饲料薄膜饲养技术,设置5组不同浓度的单宁酸,在适宜条件下分别饲养绿色型、红色型豌豆蚜,测定了豌豆蚜的存活率、产蚜量、相对日均体重增长率等指标。结果表明:单宁酸对两种生物型豌豆蚜的生长发育及繁殖有明显抑制作用,且对绿豌豆蚜的抑制作用明显大于红豌豆蚜。随着单宁酸浓度升高,两种色型豌豆蚜存活率、相对日均体重增长率均下降,5mg·L-1处理12天时绿色型豌豆蚜存活率、相对日均体重增长率分别为13.3±3.3%和0.20±0.01%,红色型分别为20.0±5.8%和0.19±0.00%,与CK间差异显著(P0.05);5mg·L-1时绿豌豆蚜产蚜量和产蚜率最低,分别为2.0±0.0头/单雌和6.7±3.3%,与CK间差异显著(P0.05)。研究结果可为次生代谢物质抗豌豆蚜的生化机理研究提供理论依据和技术支持。     

Ontogenetic variation and craniometric sexual dimorphism in the social giant mole-rat,Fukomys mechowii (Rodentia: Bathyergidae), from Zambia

The degree of maxillary molar tooth-row eruption and wear were used to assign samples of the social giant mole-rat, Fukomys mechowii, from Zambia, into nine relative age classes in order to assess ontogenetic (age) variation and craniometric sexual dimorphism, with reference to body mass. Univariate and multivariate statistical analyses showed craniometric differences between age classes 1–3 and age classes 5–9, with age class 4 being intermediate between these two age class groupings. This suggests that age class 4 lies at a point on a hypothetical growth curve where growth begins to stabilize. The intermediate placement of age class 4 in multivariate space broadly coincided with body mass categorizations into juveniles (age classes 1–3; <100 g), subadults (age class 4; c. 100–150 g), and adults (age classes 5–9; >150 g). The analyses also revealed the absence of sexual dimorphism in the relatively younger age classes 1–4 but its presence in the relatively older age classes 5–9, and these results are supported by data on body mass. These results may have implications in our understanding of the population and social structures, and reproductive strategies in this little-studied giant mole-rat.     

卧龙自然保护区雪豹的生境选择偏好与食源结构特征

近年来,人类活动范围不断扩大,对雪豹(Panthera uncia)所处高海拔生态系统侵入不断增加,对雪豹生存已造成威胁。准确掌握雪豹生境选择偏好与食源结构特征,可以完善雪豹基础研究,提高雪豹保护管理效率。因此于2019年7月对卧龙自然保护区内雪豹集中分布区域进行野外调查,研究雪豹对各生境因子的选择偏好情况;分析粪便组成,明确雪豹食源结构。结果显示:雪豹偏好于海拔3500—4500 m、坡度31°—45°且地形较为崎岖的无家畜活动区域,在坡位的选择上,雪豹偏好于山脊与上坡位,避开中、下坡位与山谷。在植被类型选择上,雪豹偏好草甸与高山流石滩,同时也会选择稀疏且基径较小的灌丛。雪豹倾向于选择草本植物稀疏,低矮的区域。雪豹动物性食源以岩羊(59.26%)为主,家畜(25.93%)与啮齿目(22.22%)次之,鸟类(7.41%)占比最少。植物性食源以禾本科(59.26%)、苔藓植物(44.44%)与莎草科(33.33%)为主,灌木及其他植物占比较少。本文丰富了雪豹的基础研究内容,为卧龙及其他保护区雪豹保护管理工作中相关政策的制定提供参考依据。     

益生菌对青年鸽生长、免疫和抗氧化性能及繁殖相关基因表达的影响

本试验旨在研究丁酸梭菌和乳酸菌对青年鸽生长性能、血清免疫指标和生化指标、肝脏抗氧化指标及与繁殖相关基因表达的影响。选取80日龄左右的雌性青年鸽384只,将其随机分成4组,每组6个重复,每个重复16只。其中A组饲喂基础饲粮,B、C和D组分别在基础饲粮中添加1×10^8CFU/kg丁酸梭菌、5×10^9CFU/kg乳酸菌和5×10^9CFU/kg乳酸菌+1×10^8CFU/kg丁酸梭菌。预试期7d,试验期28d。结果表明:1)与A组相比,B、C和D组青年鸽的平均日增重分别提高了22.0%、32.0%和22.0%,但差异不显著(P>0.05)。2)与A组相比,C和D组青年鸽血清中的免疫球蛋白M(IgM)含量显著提高(P<0.05),各组间血清中免疫球蛋白A(IgA)和免疫球蛋白G(IgG)含量差异不显著(P>0.05)。3)与A组相比,D组青年鸽血清中的总胆固醇(TC)含量显著降低(P<0.05),B、C和D组血清中的甘油三酯(TG)含量均显著下降(P<0.05)。4)与A组相比,B、C和D组青年鸽肝脏中的过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH Px)活性均显著提高(P<0.05),C和D组青年鸽肝脏中的超氧化物歧化酶(SOD)活性和总抗氧化能力(T AOC)显著提高(P<0.05),D组青年鸽肝脏中的丙二醛(MDA)含量显著降低(P<0.05)。5)与A组相比,C和D组青年鸽卵巢中的骨形态发生蛋白15(BMP15)、促卵泡素受体(FSHR)基因表达水平显著提高(P<0.05)。综上所述,在饲粮中添加丁酸梭菌和乳酸菌能够提高青年鸽肝脏抗氧化功能并增强机体免疫力,促进新陈代谢,从而提高青年鸽的生长性能,对青年鸽的繁殖潜力也起到促进作用。     

Microscopic anatomy of the oesophagus in the southern white-breasted hedgehog (Erinaceus concolor) a histochemical,stereological, and scanning electron microscope study

The present work was designed to investigate the microscopic structure of the oesophagus in the southern white-breasted hedgehog (Erinaceus concolor) using histochemical staining, Scanning electron microscope (SEM), and stereological procedures. Four adult males were included in our study. Serial sections of the entire length of the oesophagus were stained with aldehyde fuchsin, alcian blue (pH 2.5), Periodic acid Schiff (PAS), and Masson's trichrome. Then, the total volume of the oesophagus, and the total volume of its different layers, were estimated using Cavalieri's principle. The oesophageal epithelium was a non-keratinized stratified squamous type. Muscularis mucosa was present as a thick layer between lamina propria and submucosa and its thickness was increased toward the stomach. Tunica submucosa was a loose connective tissue containing an oesophageal gland with PAS-positive and AB-positive reactions throughout the submucosa and become denser toward the stomach. The tunica muscularis consisted of two distinct striated muscle layers, and its thickness was decreased toward the stomach. On SEM images, the cervical and thoracic oesophagus showed shallow folding, while the abdominal part had deeper folds. The present findings indicate that the histological properties of the oesophagus in southern white-breasted hedgehogs have slight similarities with rodents and considering its epithelium, submucosal glands and tunica muscularis more resemble with dog oesophagus. The obtained results may be quite helpful to improve the current knowledge of the histophysiology of the hedgehog gastrointestinal tract as a member of eulipotyplan mammals and as a pet for biologists and veterinarians.