Physical effectiveness of corn silage fractions stratified with the Penn State Particle Separator for lactating dairy cows.

This study evaluated the physical effectiveness of whole-plant corn silage (CS) particles stratified with the Penn State Particle Separator, composed of 19- and 8-mm-diameter sieves and a pan, for lactating dairy cows. Eight Holstein cows (27.6 ± 2.8 kg/d of milk, 611 ± 74 kg body weight; 152 ± 83 d in milk) were assigned to two 4 × 4 Latin squares (22-d periods, 16-d adaptation), where one square was formed with rumen-cannulated cows. Three CS particle fractions were manually isolated using the 8- and 19-mm diameter sieves and re-ensiled in 200-L drums. The 4 experimental diets were (% dry matter): (1) CON (control): 17% forage neutral detergent fiber (NDF) from CS (basal roughage), 31.5% starch, and 31.9% NDF; (2) PSPan: 17% forage NDF from CS + 9% NDF from CS particles <8 mm, 25.9% starch, and 37.9% NDF; (3) PS8: 17% forage NDF from CS + 9% NDF from CS particles 8 to 19 mm, 25.5% starch, and 38.3% NDF; and (4) PS19: 17% forage NDF from CS + 9% NDF from CS particles >19 mm, 24.9% starch, and 38.8% NDF. Cows fed PS8 had greater dry matter intake and energy-corrected milk yield (22.4 and 26.9 kg/d, respectively) than cows fed CON (20.8 and 24.7 kg/d) and PS19 (21.2 and 24.8 kg/d), but no difference was detected between PSPan (21.6 and 25.8 kg/d) and other treatments. Milk fat concentration was greater for PS8 than CON, with intermediate values for PSPan and PS19. Milk fat yield was greater for cows fed PS8 than CON and PS19, and cows fed PSPan secreted more fat than CON cows but were not different from cows fed the other 2 diets. Cows fed CON had a lower meal frequency than cows fed PSPan, shorter meal and rumination times than PS8, and greater meal size and lower rates of rumination and chewing than the other 3 diets. Total chewing per unit of NDF was higher for PS8 than PSPan, although neither treatment differed from CON or PS19. Cows fed PS19 had higher refusal of feed particles >19 mm than cows fed CON and PSPan. The refusal of dietary NDF and undigested NDF in favor of starch were all greater for PS19 than on the other treatments. Cows fed PS19 had a greater proportion of the swallowed bolus and rumen digesta with particles >19 mm than the other 3 diets. Cows fed CON had the lowest ruminal pH and greatest lactate concentration relative to the other 3 diets. Plasma lipopolysaccharide was higher for cows fed CON and PSPan than for cows fed PS8 and PS19, and serum d-lactate tended to be lower on PSPan than for CON and PS8. In summary, the inclusion of CS fractions in a low-forage fiber diet (CON) reduced signs of ruminal acidosis. Compared with CS NDF <8 and >19 mm, CS NDF with 8- to 19-mm length promoted better rumen health and performance of dairy cows. These results highlight the importance of adjusting CS harvest and formulating dairy diets based on the proportion of particles retained between the 8- and 19-mm sieves.

Effect of sealing strategy on the feeding value of corn silage for growing dairy heifers.

Our objective was to compare the performance of dairy heifers fed diets based on whole-plant corn silage stored in bunker silos sealed with either standard polyethylene film (white-on-black, actual thickness 121 ± 3.1 µm) covering the top surface, held in place with rows of tires every 3 m (PE) or an oxygen barrier system comprised of an ethylene-vinyl alcohol film (actual thickness 46.7 ± 2.5 µm) lining side walls and covering the silage, protected with a woven anti-UV cover and gravel bags placed around the edges and every 3 m across the silo (OB). Whole-plant corn was mechanically harvested at 39% dry matter (DM), packed in bunker silos, and sealed with PE or OB covering methods. After 6 mo of storage, silos were opened and fed to 26 Holstein heifers (260 ± 89.1 kg of shrunk body weight) for 60 d. Heifers were blocked by initial weight (13 blocks with 2 heifers each block) and housed in individual pens. Diets contained (on a DM basis) 80% corn silage (PE or OB), 17.5% soybean meal, and 2.5% mineral mix. Dry matter intake was measured daily, whereas shrunk body weight, hip height, heart girth, and body condition score were measured at the beginning and end of the experiment. Feeding behavior was recorded on d 24 and 46, and total-tract digestibility was measured from d 26 to 30 and 48 to 52. Data of intake, feeding behavior, and digestibility were averaged by animal for the whole feeding period before the statistical analysis. Data of animal performance were analyzed as a randomized complete block design. Initial shrunk body weight was used as a covariate for analyses of intake and body measures. During feed-out, silage quality was also assessed at the top (15 cm depth from upper surface) and bottom layer (135 cm depth from upper surface) and analyzed as a split-plot design. Silage stored under the OB sealing system had less yeast, mold, and NH3-N, and more lactic acid and ethanol-soluble carbohydrates. An interaction between sealing strategy and silo layer showed that OB silage had lower values of temperature, pH, anaerobic spores, acetic acid, and DM loss, and greater in vitro DM digestibility and aerobic stability, especially in the top layer. The proportion of inedible silage was lower in OB than in PE treatment (0.82 vs. 4.00% DM). Total-tract digestibility was similar between treatments, but animals that received the OB diet had higher DM intake by approximately 9% (9.39 vs. 10.20 kg/d) due to a faster eating rate and a greater number of meals per day. Therefore, OB treatment increased the digestible energy intake by 8% (26.3 vs. 28.3 Mcal/d) and average daily gain by 12% (1.08 vs. 1.21 kg/d). Body condition score change was similar between treatments, but heifers fed OB had greater heart girth and tended to have higher hip height. In conclusion, replacing a standard PE film with an OB sealing system improved silage conservation and performance of growing dairy heifers.

Dual effect of serotonin on the dendritic growth of cultured hippocampal neurons: Involvement of 5-HT1A and 5-HT7 receptors.

Serotonin acts through its receptors (5-HTRs) to shape brain networks during development and modulates essential functions in mature brain. The 5-HT1AR is mainly located at soma of hippocampal neurons early during brain development and its expression gradually shifts to dendrites during postnatal development. The 5-HT7R expressed early during hippocampus development, shows a progressive reduction in its expression postnatally. Considering these changes during development, we evaluated in cultured hippocampal neurons whether the 5-HT1AR and 5-HT7R change their expression, modulate dendritic growth, and activate signaling pathways such as ERK1/2, AKT/GSK3ß and LIMK/cofilin, which may sustain dendrite outgrowth by controlling cytoskeleton dynamics. We show that mRNA levels of both receptors increase between 2 and 7 DIV; however only protein levels of 5-HT7R increase significantly at 7 DIV. The 5-HT1AR is preferentially distributed in the soma, while 5-HT7R displays a somato-dendritic localization at 7 DIV. Through stimulation with 5-HT at 7 DIV during 24h and using specific antagonists, we determined that 5-HT1AR decreases the number of primary and secondary dendrites and restricts the growth of primary dendrites. The activation of 5-HT1AR and 5-HT7R promotes the growth of short secondary dendrites and triggers ERK1/2 and AKT phosphorylation through MEK and PI3K activation respectively; without changes in the phosphorylation of LIMK and cofilin. We conclude that 5-HT1AR restricts dendritogenesis and outgrowth of primary dendrites, but that both 5-HT1AR and 5-HT7R promote secondary dendrite outgrowth. These data support the role of 5-HT in neuronal outgrowth during development and provide insight into cellular basis of neurodevelopmental disorders.

Clinical trial of thiamphenicol therapy for uncomplicated gonorrhea.

The need for a safe drug that is easy to administer and not too expensive prompted a study of treatment of uncomplicated gonorrhea with a single oral dose of 2.5 g of thiamphenicol. Of 169 patients treated, 161 were cured. Of the 92 patients with acute infections, all of the 13 men and 74 (93.7%) of the 79 women were cured. Seventy-seven cases were defined as reinfection; all of the 22 men in this group were cured, as were 52 (94.5%) of the 55 women. Only minor adverse effects were noted. It is concluded that thiamphenicol is a safe and effective antibiotic for therapy of uncomplicated gonorrhea.