A simple caliper technique for the estimation of abdominal fat in live broilers

1. A caliper technique for estimating the amount of abdominal fat in live broilers is described.

2. Sixty‐three male and 47 female broilers sampled at 63 d of age from an unselected control line were used to examine the accuracy of the caliper measure in predicting abdominal fat.

3. Phenotypic correlations between caliper measure and the proportion of abdominal fat were + 0.80, +0.79 and +0.81 in males, females and the heaviest 20% of males respectively.

4. The application of the technique as an indirect means of selecting for decreased abdominal fat in commercial broiler breeding programmes is discussed.     

The use of separate root and shoot tests in the screening of herbicides for strawberries

The tolerance of strawberries to herbicides was tested by applications to the roots of plants growing in sand and by foliage applications to plants grown in compost, and compared with tolerance in the field. Dimefuron was safe as a foliar application but much more toxic than simazine when applied in sand or in the field. Metamitron caused slight injury as a foliar spray; in sand and in the field it was intermediate in toxicity between simazine and lenacil. At normal rates propachlor was safe as a foliar spray and much safer than lenacil when applied in sand. High rates had no adverse effect in the field. Ethofumesate and pendimethalin caused some temporary stunting when applied to foliage, but were less toxic than lenacil when applied to roots in sand. Field applications of both herbicides at 1–1.5 kg/ha were safe. Foliage sprays of bentazone, oxadiazon and oxyfluorfen severely damaged the sprayed leaves, but these herbicides were less active than lenacil when applied to the roots. In the field they caused severe leaf damage, but by the end of the growing season the plants had recovered. The experiments demonstrated the value of separate root and shoot activity tests for indicating which herbicides merit further field testing.     

Metabolic fate of [14C]endrin in bluegill fish

Bluegill absorbed 85% of 1 ppb of endrin from water within 48 hr under static exposure conditions. The absorbed radiocarbon was eliminated linearly with a half-life of about 4 weeks. Analyses of eliminated radioactivity revealed only conjugated metabolites. 12-anti-Hydroxyendrin and 12-syn-hydroxyendrin were tentatively identified by cochromatography using thin-layer chromatography/autoradiography and gas chromatography. These metabolites were also present as conjugates in the fish organs. Seventy-three percent of the absorbed radioactivity recovered from fish extracts was in the form of unchanged endrin.     

Studies on bovine demodecosis in northern Nigeria

Summary The study reported in the present paper discusses the clinical and histological picture of bovine demodecosis and the morphology of Demodex mites as seen in four cows suffering from generalized demodecosis. There were no clinical signs of other skin affections. Changes in both the number and the appearance of visible skin lesions were seen and related to the level of nutrition and the exposure to sunshine of the cattle. Histological sections of some skin nodules showed the presence of mite colonies in the hair follicles. Only adults were seen in the sebaceous glands. Microscopical study of the morphology of the mites revealed the presence of two types of demodicids in the skin lesions and three types from epilated eyelashes. Morphological criteria are presented to aid in identification of species and of life stages.     

Precocene II metabolism: Comparative in vivo studies among several species of insects,and structure elucidation of two major metabolites

Several species of insects, exhibiting varying responsiveness to the juvenile hormone antagonist precocene II (6,7-dimethoxy-2,2-dimethylchromene), were challenged topically with a tritiated preparation of the title compound. Metabolism of [³H]precocene II was subsequently examined by withdrawing hemolymph samples from treated animals at appropriate time intervals and characterizing the extractable radiolabel chromatographically. Quantitative (or qualitative) differences observed between the respective metabolic profiles were found not correlative with specimen sensitivity to precocene. Production of two heretofore unreported metabolites, identified by spectral and chemical means as O-β-glucosides of 6- and 7-monodemethylated precocene II, was demonstrated in both sensitive and insensitive species. No evidence for the presence of a hemolymphborne, biologically effective “activated metabolite” produced in vivo by precocene-susceptible insects could be found. The latter finding may well argue for in situ bioactivation of precocene at the target tissue(s) by these sensitive insects.     

An Approach to Forecasting the Incidence of Potato and Cereal Aphids in Scotland1

Many potato and cereal infesting aphids in Scotland are either completely cr partially anholocyclic. This makes forecasting their first appearance and abundance on crops difficult, when compared with holocyclic species such as Aphis fabae Scopoli. This paper describes an analysis of the early movement of nine aphid species, commonly found on potatoes and cereals in Scotland, in relation to winter and early spring climate. Data on their early movement have been extracted from the catches in three of the sjx.12–2.rn suction traps now operating in Scotland in cooperation with the Rothamsted Insect Survey. The particular importance of early spring temperature has been established. The extension of this work to develop a predictive forecast of summer activity of anholocyclic aphid species is discussed. En Ecosse, une forte proportion de pucerons des pommes de terre et des céréales est entièrement ou partiellement anholocyclique. Ceci complique la prévision sur le moment de leur première apparition et sur leur abondance par rapport aux espéces holocycliques telles qu'Aphis, fabae. Cette étude concerne les déplacements précoces de neuf espéces de pucerons retrouveés fréquemment sur les pommes de terre et les céSreales. Les données sur les deplacements ont été obtenues à partir de trois des six piegès à succion de I2,2 m installes en Ecosse en cooperation avec le « Rothamsted Insect Survey », Il est apparu que la température printanière revêt une importance particuliere. Les recherches se poursuivent dam le but d'établir des prévisions sur le développement estival des espèces anholocycliyues de pucerons.     

Insect epoxide hydrolase: Properties of a purified enzyme from the southern armyworm (Spodoptera eridania)

An epoxide hydrolase purified from midgut microsomes of southern armyworm (Spodoptera eridania) larvae exhibited high activity toward monosubstituted epoxides (1,2-epoxyoctane, 1,2-epoxypropane, and styrene oxide) and lower activity toward cis-1,2-disubstituted epoxides (cyclohexene oxide, and the cyclodienes HEOM, HCE, and chlordene epoxide). Trisubstituted epoxides (2-methyl-2,3-epoxyheptane and JH-1) as well as several cyclodiene insecticides (dieldrin, endrin, endo-epoxyaldrin, and anti-heptachlor epoxide) were refractory to enzymatic attack. It is concluded that both lipophilic and steric factors dictate the substrate specificity of the enzyme. With cyclohexene oxide the enzyme yields the 1R, 2R enantiomer of the trans-diol. The purified enzyme is inhibited by several epoxides and mixed-function oxidase inhibitors and the potency of 3,3,3-trichloro-1,2-epoxypropane and sodium picrylsulfonate suggest the importance of electronic factors in the inhibitory mechanism. Studies with specific amino acid modifiers suggest the presence of an essential lysine or histidine residue at the active site and indicate that the enzyme lacks a metal ion requirement and an essential cysteine residue. The purified enzyme has a molecular weight of 46,000 daltons and amino acid analysis and immunochemical studies show it to be very similar to, but not identical with, the epoxide hydrolase from mammalian liver microsomes.