Reproduction in three species of rainbowfish (Melanotaeniidae) from rainforest streams in northern Queensland, Australia

Abstract – The reproductive biology of three species of rainbowfish (Melanotaeniidae) in northeastern Australian rainforest streams was investigated. Two species, Melanotaenia eachamensis and Cairnsichthys rhombosomoides are endemic to the area, whereas the third, M. splendida splendida, is more widespread. The species were all highly fecund, producing many hundreds of eggs between 1.10 and 1.24 mm in diameter. Melanotaenia eachamensis was the most fecund, produced the largest eggs of the three species, and consequently exhibited the greatest maternal investment (as measured by gonadosomatic index). The majority of reproductive effort occurred during the dry season, although reproductively active fish were present year-round for each of the species, but particularly so for M. s. splendida and C. rhombosomoides. No evidence for a role by temperature or photoperiod as environmental cues for reproduction was found, and it was suggested that gonad development was strongly tied to somatic growth. The concentration of reproduction to the dry season ensures that larvae are produced during a period of relatively stable and benign physical conditions. Comparison of temporal changes in gonadosomatic index values suggest that the spawning season of M. eachamensis , which occurs in high-elevation streams, is more restricted and commences about 1 month earlier than either other species. A similar phenology was observed for the M. s. splendida population found at high elevation and highlights the potential for spatial differences in stream productivity to influence life history. ^Note     

Viral and bacterial agents associated with experimental transmission of infectious proventriculitis of broiler chickens.

Proventriculitis of broilers can be reproduced by oral inoculation of day-old chicks with a proventricular homogenate from affected 3-wk-old broilers. The objective of the following studies was to isolate from this homogenate viral and bacterial isolates that could produce proventriculitis. A monoclonal antibody to infectious bursal disease virus (IBDV) was used to precipitate virus from the homogenate. A primary chicken digestive tract cell culture system was also used to isolate virus from a 0.2-microm filtrate of the homogenate, and a bacterium was also isolated from the homogenate. In trial 1, day-old birds were orally inoculated with either proventriculus homogenate or monoclonal antibody immunoprecipitated IBDV (MAB-IBDV). At 4, 7, 14, and 21 days postinfection (PI), 12 birds from each treatment group were subjected to necropsy. In trial 2, day-old birds were orally inoculated with either infectious proventriculus homogenate, suspect virus isolated in cell culture and propagated in embryo livers and spleens, or a bacterial isolate. Twelve birds from each treatment were subjected to necropsy at days 7, 14, 21, and 28 PI. In trial 3, treatments were maintained in negative pressure isolation chambers, and an additional treatment included virus plus bacterial isolate. Twenty-four birds from each treatment were subjected to necropsy at day 21 PI. In trial 1, infectious homogenate decreased body weight and relative gizzard weights at 4, 7, 14, and 21 days PI. Proventriculus relative weight was increased at days 7, 14, and 21 PI, and proventriculus lesion scores were increased at days 14 and 21 PI. Bursa/spleen weight ratios were decreased at day 14, and feed conversion was increased at days 4 and 21. The MAB-IBDV treatment decreased proventriculus and gizzard relative weights at day 4 PI, increased proventriculus lesion scores and bursa/spleen weight ratios at day 14, and decreased heterophil/lymphocyte ratios at day 21. In trial 2, all infected birds had significantly higher mean relative proventriculus weights at 21 days PI and had higher 4-wk mean proventriculus scores as compared with both control groups. In trial 3, birds treated with homogenate and birds treated with both suspect virus and the bacterial isolate had significantly higher proventriculus lesion scores; higher relative weights of proventriculus, gizzard, liver, and heart; lower body weights; and lower relative bursa weights compared with the saline control group. These studies suggest that infectious proventriculitis has a complex etiology involving both viral and bacterial infection.     

Sinnesphysiologische Untersuchungen an Schmetterlingsraupen und ihre praktische Bedeutung

Ohne Zusammenfassung     

Puncture Wounds of the Navicular Bursa in 38 Horses A Retrospective Study

The medical records of 38 horses with puncture wounds of the navicular bursa were reviewed. Only 12 horses had a satisfactory outcome (breeding or riding). Of the remaining 26 horses, 19 were euthanized, five were sold due to persistent severe lameness, one died, and one was lost to long-term follow-up. Different combinations of conservative management prior to surgical debridement and drainage of the navicular bursa were unsuccessful in resolving the condition. Horses that were treated surgically within 1 week of the injury and had a hind leg affected had the best chance of a satisfactory outcome. Additional wound debridement was necessary in 15 horses after initial surgical treatment. The most common complications encountered were navicular bone osteomyelitis and sepsis of the deep digital flexor tendon. Thirteen of 14 horses that had rupture of the deep digital flexor tendon and subluxation of the distal interphalangeal joint had an unsatisfactory outcome. One mare subsequently developed ankylosis of the distal interphalangeal joint and was a useful brood mare. Two horses that had biaxial palmar digital neurectomy because of persistent lameness were later euthanized because of navicular bone fracture and rupture of the deep digital flexor tendon. Results from limited numbers of bacterial cultures and antibiotic sensitivities suggest that penicillin and an aminoglycoside antibiotic should be used as initial antibiotic therapy. Immediate surgical debridement and appropriate antibiotic treatment are recommended as the minimum therapy for penetrating wounds of the navicular bursa in horses.     

大蒜根蛆的发生规律及防治技术

对湖北省当阳市大蒜根蛆的发生规律、不同品种的抗虫性及药剂防治进行了调查试验。结果表明，大蒜根蛆在湖北1年发生2代，第1代根蛆危害时期为9月8～26日，第2代为9月25日至10月20日，第2代根蛆发生量大，危害严重；不同大蒜品种根蛆危害差异不大；药剂防治以10％地友GR处理土壤防效较好，为88.8％，叶面喷雾以2.5％肯打EC防效较好，为77.7％。     

Characterization of monoclonal antibodies directed against swine leukocytes

Hybridomas were produced from fusions of the SP2/0 mouse myeloma with splenic cells from: 1) an outbred Sprague Dawley rat immunized with swine peripheral blood mononuclear (PBM) cells; 2) a (CBA/NDub X BALB/c Dub) F1 mouse immunized with concanavalin A (Con A) activated swine PBM cells and 3) a (BALB/c Dub X C3H/He Dub) F1 mouse immunized with swine thymocytes. The resulting supernatants were screened by a microcytotoxicity assay for activity against swine PBM cells. Four hybridomas (MSA1, MSA2, MSA3 and MSA4) were selected, cloned and characterized by their cell reactivity and effect on mitogenic assays. MSA1 and MSA2 belong to the rat IgG2b subclass. MSA3 and MSA4 are of the mouse IgG2a subclass. These monoclonal antibodies reacted in the following manner: MSA1 with monocytes, granulocytes, red blood cells and bone marrow cells; MSA2 with subset of T cells; MSA3 with B cells and subsets of T cells and monocytes (class II molecule) and MSA4, a pan-T cell reagent (E-rosette receptor). The involvement of the various cell types reactive to the different monoclonal antibodies in the mitogenic response of swine PBM cells to Con A, phytohemagglutinin (PHA) or pokeweed mitogen (PWM) was investigated by cellular depletion with monoclonal antibody plus complement. Cellular depletion of PBM cells with the following monoclonal antibodies plus complement treatment resulted in: MSA1, almost total reduction in the mitogenic response to low doses of Con A or PWM; MSA2, partial reduction in the proliferative responses to any concentration of Con A, PHA or PWM; MSA3, partial reduction in proliferative responses to low concentrations of Con A or PWM and 4) MSA4, total elimination of any proliferative response to Con A, PHA or PWM.