Studies of the energy and protein requirements of the growing guinea-fowl.

1. Guinea-fowl of both sexes and female chickens were fed from 1 to 12 weeks on diets the energy concentration of which was constant at either 2-6, 2-9 or 3-2 Mcal/kg (10-8, 12-1 or 13-4 MJ/kg) while the calorie to protein ratios were changed, for some groups, from 124 to 157 or 200 at 4 and 8 weeks. 2. Guinea-fowl, but not chickens, were unable to overconsume when the protein concentration was low with the result that the body fat content was not reduced when the protein concentration was increased. 3. In the second trial the ME level of the diets was fixed at 12-6 MJ/kg while the protein content was varied, from 21 to 28% in the diets fed to 6 weeks of age and from 15 to 24% in those fed from 6 to 12 weeks. 4. It is concluded that for the growing guinea-fowl the diet should contain 12-6 MJ ME/kg, the protein concentration reducing from 24 to 26% in the period 0 to 4 weeks to 19 to 20% in the period 4 to 8 weeks and to 16% or less in the period 8 to 12 weeks.     

Efficacy of pre-treatment with lufenuron for the prevention of Microsporum canis infection in a feline direct topical challenge model

Oral lufenuron is reportedly an effective treatment for some cats with dermatophytosis. The purpose of this study was to determine if lufenuron, when used as a pre-treatment prior to challenge exposure, would be protective against the development of infection after the direct topical application of fungal macrocondia (Microsporum canis spores). Three groups (n = 6/group) of juvenile cats were treated with either monthly oral lufenuron (30 or 133 mg/kg) or placebo. After 2 months of treatment, kittens were challenged using 10(5)Microsporum canis spores applied to the skin under occlusion. Cats were examined weekly and the following data collected: Wood's lamp examination; scoring for scale/crust, erythema and induration; lesion size; and the development of satellite lesions. Fungal cultures were performed bi-weekly. All cats became infected; the infections progressed, and then regressed, in a similar fashion in all groups. There were no consistent statistically significant differences in weekly infection scores between treated and untreated cats throughout the study. Treated cats did not recover faster than untreated cats. We conclude that oral lufenuron at the dosing schedule and conditions used in this study did not prevent dermatophytosis or alter the course of infection by direct topical challenge.     

Nuclear receptor and target gene mRNA abundance in duodenum and colon of dogs with chronic enteropathies

Nuclear receptors (NR), such as constitutive androstane receptor (CAR), pregnane X receptor (PXR) and peroxisome proliferator-associated receptors alpha and gamma (PPAR, PPARγ) are mediators of inflammation and may be involved in inflammatory bowel disease (IBD) and food responsive diarrhea (FRD) of dogs. The present study compared mRNA abundance of NR and NR target genes [multi drug-resistance gene-1 (MDR1), multiple drug-resistance-associated proteins (MRD2, MRD3), cytochrome P450 (CYP3A12), phenol-sulfating phenol sulfotransferase (SULT1A1) and glutathione-S-transferase (GST A3-3)] in biopsies obtained from duodenum and colon of dogs with IBD and FRD and healthy control dogs (CON; n = 7 per group). Upon first presentation of dogs, mRNA levels of PPAR, PPARγ, CAR, PXR and RXR in duodenum as well as PPARγ, CAR, PXR and RXR in colon were not different among groups (P > 0.10). Although mRNA abundance of PPAR in colon of dogs with FRD was similar in both IBD and CON (P > 0.10), PPAR mRNA abundance was higher in IBD than CON (P < 0.05). Levels of mRNA of MDR1 in duodenum were higher in FRD than IBD (P < 0.05) or CON (P < 0.001). Compared with CON, abundances of mRNA for MRP2, CYP3A12 and SULT1A1 were higher in both FRD and IBD than CON (P < 0.05). Differences in mRNA levels of PPAR and MRP2 in colon and MDR1, MRP2, CYP3A12 and SULT1A1 in duodenum may be indicative for enteropathy in FRD and (or) IBD dogs relative to healthy dogs. More importantly, increased expression of MDR1 in FRD relative to IBD in duodenum may be a useful diagnostic marker to distinguish dogs with FRD from dogs with IBD.     

Effects of intra-mammary bacterial infection with coagulase negative staphylococci and stage of lactation on shedding of epithelial cells and infiltration of leukocytes into milk: comparison among cows, goats and sheep

The effects of mammary gland bacterial infection and stage of lactation on leukocyte infiltration into the mammary gland were compared among cows, goats and sheep. Animals were at two stages of lactation: mid or late. In mid-lactation animals, bacterial-free glands and coagulase negative Staphylococcus (CNS)-infected glands were compared. In late lactation only uninfected glands were studied. Of mid-lactation bacteria-free animals, goats had the highest number of leukocytes and % polymorphonuclears (PMNs), whereas sheep had the lowest and leukocytes number in cows were intermediate between sheep and goats. Based on %PMN, two cell clusters were found in sheep, which overlapped with the parallel cell clusters of cows and goats, but with a slightly higher number of leukocytes in each cell cluster. At late lactation, goats had higher values for %PMN and leukocyte numbers in comparison to cows, which had a similar cellular profile to sheep. The cellular immune response to CNS infection was similar for the three animal species, although the number of cells was different, while the basal cell level at mid-lactation and especially at the end of lactation was species specific.     

Citric acid extraction—An underestimated method in forest nutrition?

Since recent studies reveal citric acid to be favorable for estimating plant‐available P in soils, we investigated if it can also be used for assessing other nutrients. According to our results, it provides stronger correlations with the tree nutrition for Mg (beech, spruce), Ca+K (beech) and Fe (spruce) than the standard methods for determining exchangeable cations. Thus, when estimating plant‐available P by citric acid‐extraction, these cations should be additionally measured in ICP analysis.     

Nitrogen retention and plant uptake on a highly weathered central Amazonian Ferralsol amended with compost and charcoal

Leaching losses of N are a major limitation of crop production on permeable soils and under heavy rainfalls as in the humid tropics. We established a field trial in the central Amazon (near Manaus, Brazil) in order to study the influence of charcoal and compost on the retention of N. Fifteen months after organic‐matter admixing (0–0.1 m soil depth), we added ¹⁵N‐labeled (NH₄)₂SO₄ (27.5 kg N ha^–1 at 10 atom% excess). The tracer was measured in top soil (0–0.1 m) and plant samples taken at two successive sorghum (Sorghum bicolor L. Moench) harvests. The N recovery in biomass was significantly higher when the soil contained compost (14.7% of applied N) in comparison to only mineral‐fertilized plots (5.7%) due to significantly higher crop production during the first growth period. After the second harvest, the retention in soil was significantly higher in the charcoal‐amended plots (15.6%) in comparison to only mineral‐fertilized plots (9.7%) due to higher retention in soil. The total N recovery in soil, crop residues, and grains was significantly (p < 0.05) higher on compost (16.5%), charcoal (18.1%), and charcoal‐plus‐compost treatments (17.4%) in comparison to only mineral‐fertilized plots (10.9%). Organic amendments increased the retention of applied fertilizer N. One process in this retention was found to be the recycling of N taken up by the crop. The relevance of immobilization, reduced N leaching, and gaseous losses as well as other potential processes for increasing N retention should be unraveled in future studies.     

Separation of protein and lactose intake over meals dissociates postprandial glucose and insulin concentrations and reduces postprandial insulin responses in heavy veal calves

The present study examined, at identical daily nutrient intakes, the impact of separating protein and lactose intakes across two daily meals on the metabolic and endocrine status in heavy veal calves. Calves were assigned to one of six degrees of separating protein and lactose over the two meals (termed nutrient synchrony, SYN 1-6; 6 calves/treatment). They were fed the protein-rich (P-)meal and the lactose-rich (L-)meal at 06:00 and 18:00h, respectively, or vice versa. At SYN 1, calves were fed with 50% of the daily protein and 50% of the daily lactose intake in each meal. Protein and lactose were iso-energetically exchanged between the two daily meals from SYN 1 to 6. At SYN 6, 85% of the daily protein and 20% of the daily lactose was fed in the P-meal and the remainder in the L-meal. Blood samples were collected hourly during 24h. Mean 24h glucose concentrations increased and insulin concentrations decreased from SYN 1 to 6. Postprandial 5h areas under concentration curves (AUC(0-5h)) of glucose increased with increasing meal lactose content. AUC(0-5h) of non-esterified fatty acids increased after P- and L-meals from SYN 1 to 6. Urea concentrations increased after L-meals from SYN 1 to 6, but decreased after P-meals from SYN 1 to 6. Insulin AUC(0-5h) decreased after L-meals and after P-meals from SYN 1 to 6. Nutrient asynchrony did not affect insulin-like growth factor-1, glucagon, growth hormone, leptin, 3,5,3'-triiodothyronine and thyroxine. In conclusion, separation of protein and lactose intake over meals inhibited insulin responses to a lactose-rich meal in heavy veal calves despite high plasma glucose concentrations.     

Low-dietary protein intake induces problems with glucose homeostasis and results in hepatic steatosis in heavy milk-fed calves

We studied effects of protein intake at two protein-free energy intake levels on plasma glucose and insulin concentrations, urinary glucose excretion and on liver and intestinal fat content in milk-fed veal calves. Two experiments were performed at body weights (BW) of 80-160 kg (mean 120 kg; Exp. 1) and 160-240 kg (mean 200 kg; Exp. 2). In each experiment, 36 calves were allocated to one of six protein intake levels, at each of two energy intake levels. Digestible protein intakes ranged between 0.90 and 2.72 g nitrogen (N)/(kg BW(0.75) x d) in Exp. 1 and between 0.54 and 2.22 g N/(kg BW(0.75)x d) in Exp. 2. The two energy intake levels were kept constant on a protein-free basis and were 663 and 851 kJ/(kg BW(0.75) x d) in Exp. 1 and 564 and 752 kJ/(kg BW(0.75)x d) in Exp. 2. Blood samples were taken between 5 and 6h post-feeding at 14-d intervals until calves reached target BW, and liver fat mass was determined at slaughter. Urinary glucose excretion was quantified at 120 and 200 kg BW in Exps. 1 and 2, respectively. Increased protein-free energy intake increased plasma glucose concentrations and urinary glucose losses in 200 kg calves, but not in 120 kg calves. Increasing protein intake decreased plasma glucose, urinary glucose and plasma insulin in both experiments. Liver fat content decreased with increasing protein intake. In conclusion, long-term low-dietary protein intake increased hyperglycemia, hyperinsulinemia, glucosuria and hepatic steatosis in heavy milk-fed calves, likely associated with increased insulin resistance.