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In: Book of Abstracts of the 68th Annual Meeting of the European Federation of Animal Science
Authors: , , and

Optimal conditions for high frequency shoot bud regeneration from leaf callus of Trema orientalis (Blume) Linn. were studied. The regeneration rate was controlled by the growth regulators, the age and the source of the explants, and the illumination conditions. Irrespective of illumination conditions, shoot bud regeneration was achieved only in media containing benzyladenine (BA) + α-naphthaleneacetic acid (NAA) combinations, with the best results being obtained in the presence of 2.5 mg/1 BA and 0.25–0.5 mg/1 NAA. The morphogenic response was less frequent in the calluses derived from leaf explants of the mature trees compared to those of the in vitro-grown seedlings. The rate of shoot bud regeneration was more pronounced in the cultures maintained for 4 weeks in the light (16-h photoperiod) than the cultures incubated in the dark. Regenerated shoots were rooted on the medium containing 1/2 strength basal Murashige and Skoog (MS) salts supplemented with 0.01 mg/1 NAA or indole-3-butyric acid (IBA). The rooted plantlets were established in the greenhouse.

In: Israel Journal of Plant Sciences
Authors: , , and

Somatic embryogenesis was achieved from callus derived from immature cotyledons of Acacia catechu Willd on Woody Plant Medium (WPM) supplemented with 13.9 μM kinetin and 2.7 μM α-naphthaleneacetic acid. Somatic embryos formed when the calli were grown for 2 weeks in the dark followed by incubation in the light with a 16-h photoperiod. Embryogenesis did not occur with continuous incubation in either the dark or the light. The addition of L-proline (0.87–5.21 mM) to the medium promoted the development of somatic embryos and induced secondary somatic embryogenesis. The light-green somatic embryos germinated on half-strength Murashige and Skoog (MS) medium supplemented with 2% (w/v) sucrose devoid of growth regulators. Somatic embryos germinated into plantlets which were hardened in the greenhouse and subsequently transferred to the field.

In: Israel Journal of Plant Sciences
In: Nematologica

Methane is a greenhouse gas produced by ruminants and contributes to global warming. It is assumed that reducing CH4-emissions is possible by genetic selection. However, phenotypic characterisation of the animals for methane emission is challenging. By using respiration chambers, it is not possible to screen large numbers of cows for methane production. The purpose of the study is to deduce an improved milk fatty acid marker to predict individual methane emission for identifying low-CH4- emitting cows. Twenty lactating, half-sib Holstein cows were fed 4 diets: rich in starch (S), starch + linseed (SL), rich in fibre (RF), fibre + linseed (RFL). In experimental week (EW) 1, the cows were switched step-wise from standard TMR to 1 of the 4 diets which were fed until EW 6. Thereafter, from EW 7 to 12, diet was changed from RF to RFL, and from S to SL or vice versa. Methane emissions were recorded in EW 4 and 10 for 48 h each using open circuit respiration chambers. During respiration measurements a milk aliquot was collected and analysed by near-infrared spectroscopy. So far, data from 6 cows/diet were analysed using PROC MIXED of SAS. Our findings indicate a methane lowering effect with linseed supplementation. Furthermore, the experimental diets cause a wide variation of methane output associated with significant changes of the saturated / unsaturated fatty acids ratio in milk fat. This suggests that the selected experimental diets are suitable to construct a regression equation to predict individual methane emission from milk fatty acids.

In: Energy and protein metabolism and nutrition

Mineral and heavy metal accumulation in black soldier fly (Hermetia illucens) larvae (BSFL) is of growing interest. The bioaccumulation of elements in BSFL is usually assessed by a bioaccumulation factor (BAF), which is the ratio between the concentration of an element in the organism and in its feeding substrate. Recently, a new index, i.e. bioaccumulation index (BAI), which represents the relative increase in the concentration of a given element to its initial concentration has been proposed. The BAI is claimed to be a more valid alternative to the BAF, especially because it takes into account the initial element concentration of the larvae. This work assesses BAF and BAI in comparison with true element retention rate in BSFL. Using an experimental setup that included the element turnover of BSFL in two different feeding regimes (with and without a different substrate for neonatal larvae), we show that: (1) the initial element concentration in BSFL is only a tiny fraction (<0.1%) of the total element pool in the system, implying that the feeding substrate is the main source of elements to be accumulated by the growing larvae; (2) each element has a specific concentration pattern from the start to the end of feeding experiments. Furthermore, in cases where both neonatal diets and experimental feeding substrates are used during the larval growth period, BAI can be confounded by time/age with diet-related effects. From an agri-food perspective of rearing BSFL for element accumulation, the retention rate of elements from the feeding substrate to the larval body remains the most valid evaluation parameter. The results of input-output calculations and element-unspecific correlations suggest a higher agreement of true element retention rate with BAF than with BAI. Therefore, we propose to assess the element accumulation in BSFL by retention rate followed by BAF under laboratory conditions.

Open Access
In: Journal of Insects as Food and Feed
In: XX International Grassland Conference: Offered papers

Maize lethal necrosis (MLN) disease caused by a combined infection of Maize chlorotic mottle virus (MCMV) and any cereal infecting potyvirus is a threat to food security in Sub-Saharan Africa (SSA). Resistance to potyvirus has been extensively studied and Mdm1 gene for potyvirus resistance on chromosome 6 of maize is linked to Y1 gene for maize endosperm colour. This study is aimed at selecting for coupling-phase recombination of potyvirus resistance and white endosperm colour. White susceptible maize lines CML333 and CML277 were crossed with a yellow resistant line, Pa405, to produce F1 and F2 progenies. Progenies were screened using molecular markers to recover 22 white endosperm recombinants. 22 selections were advanced to F3 recombinant families, and 10 were assayed for their responses to Maize dwarf mosaic virus (MDMV) and Sugarcane mosaic virus (SCMV). Four families segregated for SCMV resistance, selection of homozygous recombinants within these families will provide lines appropriate for improving lines with resistance to SCMV and MLN resistance in SSA.

Open Access
In: Afrika Focus