Tubers from leaf-bud cuttings: A tool for potato seed certification and breeding programs

The use of leaf-bud cuttings as a tool for rapid clonal increase was studied in 6 cultivars. Small tubers were obtained directly from leaf-bud cuttings maintained for 7 weeks in sand-filled pots or benches. The tubers ranged in size up to 1 1/4 inches (3cm) in diameter. The number of leaf-bud cuttings ranged from 37 to 288, depending on size of mother plant. They averaged 114 cuttings. Almost all of the leaf-bud cuttings produced tubers. The procedure is fast, simple, and provides for rapid increase of selected stocks.     

Deaths and years of life lost due to suboptimal breast-feeding among children in the developing world: a global ecological risk assessment

OBJECTIVE: We estimate attributable fractions, deaths and years of life lost among infants and children < or = 2 years of age due to suboptimal breast-feeding in developing countries. DESIGN: We compare actual practices to a minimum exposure pattern consisting of exclusive breast-feeding for infants < or = 6 months of age and continued breast-feeding for older infants and children < or = 2 years of age. For infants, we consider deaths due to diarrhoeal disease and lower respiratory tract infections, and deaths due to all causes are considered in the second year of life. Outcome measures are attributable fractions, deaths, years of life lost and offsetting deaths potentially caused by mother-to-child transmission of HIV through breast-feeding. SETTING: Developing countries. SUBJECTS: Infants and children < or = 2 years of age. RESULTS: Attributable fractions for deaths due to diarrhoeal disease and lower respiratory tract infections are 55% and 53%, respectively, for the first six months of infancy, 20% and 18% for the second six months, and are 20% for all-cause deaths in the second year of life. Globally, as many as 1.45 million lives (117 million years of life) are lost due to suboptimal breast-feeding in developing countries. Offsetting deaths caused by mother-to-child transmission of HIV through breast-feeding could be as high as 242,000 (18.8 million years of life lost) if relevant World Health Organization recommendations are not followed. CONCLUSIONS: The size of the gap between current practice and recommendations is striking when one considers breast-feeding involves no out-of-pocket costs, that there exists universal consensus on best practices, and that implementing current international recommendations could potentially save 1.45 million children's lives each year.     

Effects of supplemental dietary vitamin C on quality of semen from Nile tilapia (Oreochromis niloticus) breeders

The objective of this study was to evaluate the effects of vitamin C on growth and quality of semen from Oreochromis niloticus breeders. One hundred and sixty males were fed with different levels of vitamin C (0, 261, 599 and 942 mg/kg diet). The higher weight values were recorded for 599 (166 g) and 942 (175 g) mg of vitamin C/kg diet. Sperm motility, vigour and concentration were higher with 599 and 942 mg of vitamin C/kg diet. The semen volume, gonadosomatic index and plasma protein data from the last week showed a direct relationship with increasing levels of vitamin C. No changes were observed in the hepatosomatic index and blood glucose. The haematocrit and erythrocyte showed higher values estimated by equations derived at 850 and 638 mg vitamin C/kg diet, respectively. The leucocytes were inversely proportional to the increasing levels of vitamin C. After 100 days of feeding, animals fed the diet containing 942 mg vitamin C/kg diet had higher sperm motility, linearity, curvilinear velocity, straight line velocity and average path velocity (p < .05). Higher values of beat cross‐frequency were observed in broodfish fed diets containing 942 and 599 mg vitamin C/kg. The different vitamin C levels did not cause differences in straightness, lateral head displacement and sperm morphology. For Nile tilapia males on intensive rearing and handling conditions, vitamin C levels between 599 and 942 mg/kg may be used for a better performance and quality of semen.     

Effect of selenium supplementation on semen characteristics of Brazil's ram

The aim of this study was to investigate the effects of different concentrations of oral supplementation with selenium (Se) upon ram sperm parameters. Thirty rams managed in stall under intensive system were used and divided into five groups (six animals per group) as follows: control group (G1) mineral mixture supplementation without Se, group 2 (G2) mineral mixture supplemented with 5 mg/kg Se, group 3 (G3) supplemented with 10 mg/kg Se, group 4 (G4) supplemented with 15 mg/kg Se and group 5 (G5) supplemented with 20 mg/kg Se. For each group, there was an adjustment period of 14 days. The experimental period was 350 days. Every 56 days, the animals were weighed and semen samples were collected by electroejaculation. Semen analysis included volume, mass moviment, total motility, vigour, concentration and morphology. For plasmatic and acrosomal membrane integrity evaluation and mitochondrial membrane potential were used a combination of fluorescent probes. Differences between means values obtained by analysis of variance were verified by Tukey test with 5% probability. There was no statistical difference between treatment groups in relation to volume, mass moviment, total motility, vigour, concentration, plasma and acrosomal membrane integrity (p > .05). Sperm morphology was different between treatment groups, the G1 (0 mg of selenium) had the highest percentage of major defects (11.11 ± 1.11^a; p < .05). It was concluded that selenium decrease the percentage of sperm defects and did not directly influence on ram sperm volume, mass moviment, total motility, vigour, concentration and membrane integrity.