Augmentation of HIV-specific T cell function by immediate treatment of hyperacute HIV-1 infection

Sustained viremia after acute HIV infection is associated with profound CD4+ T cell loss and exhaustion of HIV-specific CD8+ T cell responses. To determine the impact of combination antiretroviral therapy (cART) on these processes, we examined the evolution of immune responses in acutely infected individuals initiating treatment before peak viremia. Immediate treatment of Fiebig stages I and II infection led to a rapid decline in viral load and diminished magnitude of HIV-specific (tetramer+) CD8+ T cell responses compared to untreated donors. There was a strong positive correlation between cumulative viral antigen exposure before full cART-induced suppression and immune responses measured by MHC class I tetramers, IFN-γ ELISPOT, and CD8+ T cell activation. HIV-specific CD8+ T responses of early treated individuals were characterized by increased CD127 and BCL-2 expression, greater in vitro IFN-γ secretion, and enhanced differentiation into effector memory (Tem) cells. Transcriptional analysis of tetramer+ CD8+ T cells from treated persons revealed reduced expression of genes associated with activation and apoptosis, with concurrent up-regulation of prosurvival genes including BCL-2, AXL, and SRC. Early treatment also resulted in robust HIV-specific CD4+ T cell responses compared to untreated HIV-infected individuals. Our data show that limiting acute viremia results in enhanced functionality of HIV-specific CD4+ and CD8+ T cells, preserving key antiviral properties of these cells

Effects of bacterial silage inoculants on whole-crop maize silage fermentation and silage digestibility in rams

This study evaluated the effects of ensiling whole-crop maize with bacterial inoculants, Lactococcus lactis (LL) and Lactobacillus buchneri (LB), on the fermentation and nutrient digestibility in rams. Whole-crop maize (265 DM g/kg) was ensiled for 90 days in 210 L drums with no additive, or with LL or LB. After three months, the drums were opened and the silage was sampled for fermentation characteristics. Diets were produced by mixing the whole-crop maize silage with lucerne hay (90 : 10) on an “as fed” basis, and a digestibility study was conducted using five South African Mutton Merino rams (37.2 ± 2.2 kg live weight) per treatment. Inoculating maize silage with LL and LB reduced ammonia nitrogen concentration, but did not affect silage pH. The concentration of lactic acid was increased with LL compared to the other treatments. A higher concentration of acetic acid was obtained with LB inoculation compared to the other treatments. The aerobic stability of the silage was improved with LB while it was reduced with LL inoculation, as indicated by a higher CO2 production than the latter. The intake and digestibility of dry matter, organic matter, crude protein and fibre were improved by inoculation. Furthermore, inoculations resulted in improved nitrogen retention. It was concluded that the inoculants improved silage fermentation and diet digestibility. Inoculation with LB improved aerobic stability and LL inoculation reduced it.Keywords: Alfalfa, lucerne, aerobic stability, Lactococcus lactis, Lactobacillus buchner

Effects of bacterial inoculants and an enzyme on the fermentation quality and aerobic stability of ensiled whole-crop sweet sorghum

A study was conducted to evaluate the effects of bacterial inoculation and cellulase on the fermentation quality of ensiled whole-crop sweet sorghum (WCSS, Sorghum bicolor L. Moench). The WCSS (323 g dry matter (DM)/kg, 251 g water soluble carbohydrates (WSC)/kg DM, 43 g crude protein (CP)/kg DM and 439 g neutral detergent fibre (NDF)/kg DM) was ensiled with i) no additive (control); ii) Lactobacillus buchneri (LB); iii) Lactobacillus plantarum (LP); and iv) LB+E, a combination of LB and enzyme. These treatments were ensiled in 1 L anaerobic jars for 25 days. The jars were opened on days 3, 7 and 15 to determine pH, while those of day 25 were sampled to determine nutrient composition, fermentation characteristics and aerobic stability. Inoculation reduced pH, butyric acid and ammonia-N and increased lactic acid content in sweet sorghum silage compared with the control. The aerobic stability of WCSS was improved with LB, while it was reduced with the homofermentative LP treatment compared with the control. The LB+E reduced the fibre, but increased residual WSC of silage. The aerobic stability of LB+E silage was lower than LB treated silage. Using enzymes to increase the WSC content of crops that already have high levels of WSC may result in reduced aerobic stability of silage. Further work is needed to evaluate these effects on silage produced on farm scale and on animal production performance.Keywords: Aerobic stability, enzyme, fermentation, inoculants, silag

Growth performance of feedlot weaners cattle fed diet containing different levels of cold press soya bean oilcake

Abstract The value of cold press soya bean oil cake (CPSBOC) as the source of protein in beef cattle was evaluated. CPSBOC was included in the diets of beef weaners at different levels i.e. 0%, 6%, 13% and 20%. The control diet contained cotton seed oil cake (CSOC) as a protein source. The diets were formulated to be isonitrogenous. A total of 40 weaners (20 heifers and 20 steers) at an average weight of 192.3 ± 20 kg were used. The experiment was a randomized block design with ten replicates per treatment and was conducted over 98 days. The group mass of the steers (700 ± 7.80 kg) was significantly heavier when compared with the heifers (6480 ± 7.80 kg). The average daily gain (ADG) (1.5 ± 2.72) and feed conversion ratio (FCR) (5.5 ± 0.051) of the steers was significantly better than the heifers (1.35 ± 2.72 and 5.7 ± 0.051, respectively) while the steers consume more feed (8.2 ± 14.4 kg) per day as compared to the 7.4 ± 14.4 kg consumed by heifers. The weaners that were fed the diet containing 6% and 13% inclusion of CPSBOC grew significantly better than the other treatments. According to this study, an inclusion level of CPSBOC of between 6 and 13% will yield suitable growth in feedlot cattle. More research is needed to determine the optimum inclusion level of CPSBOC

Effects of dietary inclusion of discarded cabbage (Brassica oleracea var. capitata) on the growth performance of South African Dorper lambs

A study was conducted to determine the effect of dietary inclusion of discarded cabbage (DC) on the intake and growth performance of lambs. Diets containing 0 (control, DC0), 100 g DC/kg (DC100), 150 g DC/kg (DC150) and 200 g DC/kg (DC200) were fed ad libitum to 36 South African Dorper lambs (22.0 ± 1.3 kg live weight). The dry matter intake (DMI) and lamb growth performance was reduced as the level of cabbage in the diet increased. The feed conversion rate of lambs was negatively affected by inclusion of cabbage in the diet. Diets containing cabbage had a lower DM, OM and aNDF digestibility compared with the control. Nitrogen intake and retention was lower in lambs fed diets containing cabbage. Discarded cabbage can be included in finishing diets for lambs but reduced animal performance can be expected.Keywords: By-products, digestibility, feed intake, lambs, nitrogen, supplementatio

Evaluation of potato hash silage from two bacterial inoculants and their effects on the growth performance of grower pigs

Potato hash was mixed with wheat bran at 7:3 ratio, treated with  homofermentative LAB inoculant (BMF, bonsilage forte),  heterofermentative lactic acid bacteria (LAB) (LFLB, Lalsil Fresh LB) and without LAB inoculant and ensiled in 210 L drums for 90 days. After 90 days of ensiling, concentrates that contained 40% potato hash silage (PHS) were formulated and the treatment groups were control (no silage), untreated PHS, BMF treated PHS and LFLB treated PHS. The diets were fed to 64 growing pigs (60 days old and 30.4 ± 2.3 kg body mass). The pigs were allocated in a complete randomized block design with four  treatments, and each treatment consisted of eight boars and eight sows. Pigs were fed ad libitum, feed intake was measured daily while body masses were recorded at the start and weekly throughout the experimental period. The dry matter intake (DMI) was higher in the control diet (1062 g/kg) than in the untreated PHS diets (933 g/kg), BMF treated PHS (873 g/kg) and LFLB treated PHS (919 g/kg) diets, respectively. Pigs in the control group had higher final body weight (60.77 kg), average daily gain (ADG) (551 g/d) and better feed conversion rate (FCR) (4.92 g/g) at the end of the trial compared to those in other treatment groups. It can be concluded that potato hash silage produced with or without LAB inoculants had the same effect on the growth performance of growing pigs. However, further work is needed to evaluate the effects of higher dietary inclusion levels (>40 %) of ensiled potato hash on pig growth and reproductive performance.Keywords: Potato hash, grower pigs, LAB inoculation, growth performanc

Growth performance of feedlot weaners cattle fed diet containing different levels of cold press soya bean oilcake

The value of cold press soya bean oil cake (CPSBOC) as the source of protein in beef cattle was evaluated. CPSBOC was included in the diets of beef weaners at different levels i.e. 0%, 6%, 13% and 20%. The control diet contained cotton seed oil cake (CSOC) as a protein source. The diets were formulated to be isonitrogenous. A total of 40 weaners (20 heifers and 20 steers) at an average weight of 192.3 ± 20 kg were used. The experiment was a randomized block design with ten replicates per treatment and was conducted over 98 days. The group mass of the steers (700 ± 7.80 kg) was significantly heavier when compared with the heifers (6480 ± 7.80 kg). The average daily gain (ADG) (1.5 ± 2.72) and feed conversion ratio (FCR) (5.5 ± 0.051) of the steers was significantly better than the heifers (1.35 ± 2.72 and 5.7 ± 0.051, respectively) while the steers consume more feed (8.2 ± 14.4 kg) per day as compared to the 7.4 ± 14.4 kg consumed by heifers. The weaners that were fed the diet containing 6% and 13% inclusion of CPSBOC grew significantly better than the other treatments. According to this study, an inclusion level of CPSBOC of between 6 and 13% will yield suitable growth in feedlot cattle. More research is needed to determine the optimum inclusion level of CPSBOC.Keywords: Steers, heifers, feed intake, feed conversion ratio, growt

Effects of dietary replacement of maize grain with popcorn waste products on nutrient digestibility and performance by lambs

A study was conducted to evaluate the effects of dietary replacement of maize with popcorn waste (PW) on the intake, nutrient digestibility and growth performance of lambs. Diets replacing 0, 25, 50, 75 and 100% maize with PW were formulated and fed ad libitum to 40 South African Mutton Merino lambs (25.0 ± 0.45 kg live-weight). The diets had similar intake and nutrient digestibility of dry matter (DM), organic matter (OM) and neutral detergent fibre (NDF). Lambs fed the 25 and 50% PW diets had higher intakes of crude protein (CP), metabolizable energy and ether extract compared to the other diets. Growth rate was highest (226 g/d) on the 25% diet and lowest (109 g/d) on the 75% PW diet. Best feed conversion ratio (FCR), of 5.1 (kg feed/kg live weight) was obtained with the 0% PW diet. Improved digestibility of CP and EE occurred in the 25 and 75% PW diets. Higher intake of nitrogen (N) and N retention were obtained in the 25 and 50% PW diets. Dietary replacement of >75% of maize resulted in poor animal performance (ADG 7.00). It was concluded that PW can replace up to 50% of the maize in diets for growing lambs.Keywords: Average daily gain, by-products, lambs, maize, popcor

Effects of bacterial inoculation on the fermentation characteristics and aerobic stability of ensiled whole plant soybeans (Glycine max (L.) Merr.)

The effect of bacterial inoculation on the fermentation and aerobic stability of two ensiled whole plant soybean (WPSB) cultivars was determined in a 2 x 2 factorial design. Two WPSB cultivars, Link LF6466 and Pannar 522 RR, were harvested at their R6 growth stage, chopped to 25 mm and ensiled in 1.5 L anaerobic jars. The chopped forages were treated with or without the bacterial inoculant Lalsil Dry (LD) and treatments were as follows: i) Pan control (soybean cv Pannar 522 RR with no additive); ii) Link control (soybean cv Link LF 6466 with no additive); iii) Pan LD (soybean cv Pannar 522 RR treated with LD); and iv) Link LD (soybean cv Link LF 6466 treated with LD). Jars were opened on days 3, 7, 10, 21 and 90 to determine pH. Samples of day 0 and day 90 were used to determine chemical composition and fermentation characteristics. In addition, samples of day 90 were subjected to an aerobic stability test in which they were exposed to air for five days, and CO2, pH, hours for temperature to rise above 2 ºC, yeasts and moulds were determined. Pannar cultivar had higher contents of dry matter (DM), crude protein (CP), gross energy (GE) and ether extract (EE) compared with the Link cultivar at pre-ensiling. However, Link cultivar had higher content of water-soluble carbohydrates (WSC) compared with Pannar. Inoculation with LD reduced silage DM, CP and fibre contents, and increased silage pH compared with the control. Inoculation increased silage acetic and propionic acids, but had a lower content of lactic acid (LA) and DM recovery compared with the control. When compared with the control, silage aerobic stability was improved with LD inoculation, as indicated by reduced CO2 production, and yeast and mould populations, and increased number of hours for stability after aerobic exposure. It was concluded that LD inoculant reduced silage fermentation and preservation, but improved aerobic stability of silage. Further work is needed to determine the effects of soybean silage on growth performance and production response of ruminants.Keywords: Cultivars, forages, inoculants, legumes, nutrients, silage, soybea