Effect of β-mannanase on the digestibility of diets with different protein sources in dogs determined by different methodologies

This experiment aimed at evaluating the effects of including the enzyme, β-mannanase, in dog (Canis lupus familiaris) diets based on either poultry (Gallus gallus domesticus) by-product meal (PBM) or soybean [Glycine max (L.) Merr.] Meal (SBM). The second objective was to evaluate 3 methods for determining energy and nutrient digestibility values in diets fed to dogs: total fecal collection (TFC) and use of aia or crude fiber (CF) as a marker. Eight dogs were allotted to a replicated latin square (4 by 4) design. There were 2 diets based on PBM as the major protein source and 2 diets based on SBM as the major protein source. Within each protein source, 1 diet contained no β-mannanase and 1 diet contained 0.01% β-mannanase. Diets were fed for an adaptation period of 5 d followed by 5 d of TFC. Fecal score (1 = watery feces to 5 = dry, hard pellets), pH, DM, and fecal volume were determined. The apparent total tract digestibility (ATTD) of DM, OM, CP, ether extract (EE), N-free extract (NFE), and GE, and ME content were calculated using the methods of TFC, AIA, and CF. Data were analyzed as a 2 by 2 by 3 split-split-plot design (β-mannanase, protein source, and digestibility calculation procedure). There were interactions between protein source and β-mannanase (P < 0.05). Supplementation of β-mannanase increased ATTD of nutrients and energy and ME (+ 195.3 kcal/kg) and also reduced fecal production in the diet with SBM, but not in the diet that contained PBM. There was an interaction between digestibility calculation procedure and protein source (P < 0.05). The use of AIA overestimated ATTD of the diets containing PBM, but digestibility values estimated based on TFC and CF were not different. Dogs fed diets containing SBM produced more feces with greater moisture content and lower pH compared with dogs fed the PBM diet (P < 0.05). Addition of 0.01% β-mannanase increased (P < 0.05) the digestibility and ME content of the diets containing SBM, but did not improve (P > 0.05) fecal texture. Results indicated that values for ATTD of energy and nutrients in diets containing sbm are not different if they are calculated based on TFC, AIA, or CF, but use of AIA may result in an overestimation of values for ATTD of energy and nutrients in diets containing PBM.     

Do progenitor cells from different tissue have the same phenotype?

The purpose of this work was to validate isolation methods for sheep mesenchymal stem cells (MSC) from different sources and to explore the hypothesis that MSC exhibit markers of the same phenotype independent from tissue source. Cells derived from ovine bone marrow, synovial membrane and adipose tissue were characterized using the following markers: CD44, CD45, CD11b and MHC-I. The isolated MSC were cultivated, went through osteogenic, chondrogenic and adipogenic differentiation, and were characterized by flow cytometry using mouse anti-ovine CD44, CD45 and MHC-I monoclonal antibody (mAb), and mouse anti-bovine CD11b mAb. Ovine MSC from all three sources differentiated under chondorgenic, osteogenic and adipogenic conditions. Also, MSC from the three tissues were found to express CD44 and MHC-I but lack of CD11b and CD45. The results obtained revealed that our isolation methods for the different tissues tested are valid and that MSC from the three sources studied have same immunophenotic characteristics.     

Water balance of Colostomised and non‐Colostomised hens at different ambient temperatures

1. The quantities of water gained and lost, and hence the total water balance, were determined in normal and colostomised White Leghorn laying hens at ambient temperatures of 5, 20 and 35 °G.

2. In both groups the water intake and water loss at all temperatures were well balanced.

3. Water to food ratios and water content of excreta of normal hens increased with increasing temperature.

4. The wetter excreta at 35 °C are caused by an increased urine production and not by an increased water passage through the alimentary tract.     

How many markers are enough? Factors influencing parentage testing in different livestock populations

Reliability of parentage test panels is usually based on its power to exclude wrong parentage assignments based on allele frequencies. We evaluated the rates of false exclusions and inclusions in parentage assignments, and how these results are affected by allele frequencies, panel sizes and the number of allowed mismatches. We also evaluated the reliability of parentage testing by comparing populations with distinct genetic backgrounds using pure and composite families of cattle and sheep. Allowing for 1% genotype mismatches in true parent–offspring relations provided the best compromise between false‐positive and false‐negative assignments. Pure breeds needed at least 200–210 single‐nucleotide polymorphism (SNP) markers to correctly assign relations, but between 700 and 890 markers to avoid assigning incorrect relationships. Composite breeds needed between 220 (sheep) and 500 (cattle) markers for correct assignment; 680 (cattle) to 4400 (sheep) SNPs were needed to eliminate false‐positive assignments. Allowing 0% genotype mismatches decreased false‐positive but increased false‐negative assignments, whilst a higher threshold of 2% showed the opposite effects. Panels with high minor allele frequencies (0.35–0.45) provided the best chance for correct parentage resolutions requiring fewer markers. Further, we propose that a dynamic threshold would allow adapting to population specific error rates. A comparison to the performance of the official International Society for Animal Genetics SNP panel for cattle and a recently published SNP panel for sheep showed that randomly selected markers performed only slightly worse for the applied parentage test based on opposing homozygotes. This suggests that even with carefully selected panels, only marginal assignment improvements are obtainable for a particular number of SNPs. The main point for improvement is the number of markers used. We recommend using at least 200 SNP markers for parentage testing if the aim is to reduce false‐negative results. To fully exclude false positives at least 700 markers are required.     

Coagulase-negative staphylococci as cause of bovine mastitis- not so different from Staphylococcus aureus?

In this review of the literature, mastitis-causing coagulase-negative staphylococci (CNS) and Staphylococcus aureus are compared. Staphylococci are the bacteria most commonly isolated from bovine mastitis, and CNS are now predominant over S. aureus in most countries. CNS include various species, but only a few prevail in bovine mastitis. S. aureus can cause clinical mastitis, but often causes subclinical mastitis, which remains persistent and increases milk somatic cell count. CNS, traditionally regarded as minor pathogens, seem to lack the ability to cause severe mastitis. CNS can, however, persist in the mammary gland and moderately increase milk somatic cell count. Resistance to various antimicrobials is more common in CNS than in S. aureus, but CNS mastitis responds much better to antimicrobial treatment than S. aureus mastitis.     

Swine virus-specific cytotoxic cells producing IFNγ under different conditions of virus antigenic stimulation

Flow cytometry is a useful tool to determine both the phenotype and function of immune cells during vaccination and viral infection. Since cytokine release is a hallmark of cell activation, detection of intracellular interferon (IFN)γ in cytotoxic CD8α+ cells under physiological conditions and after Aujeszky’s Disease Virus (ADV)- or Porcine Circovirus type 2 (PCV2)-swine interaction was carried out. Blood samples were collected from healthy 10-month-old pigs, ADV- or PCV2-vaccinated pigs, and PCV2-infected pigs; the levels of total IFNγ+ and CD8α+IFNγ+ cells were evaluated after PMA-ionomycin and virus-specific in vitro stimulation. High CD8α+IFNγ+ cell levels were detected in adult pigs, whereas lower virus-specific cell fractions were observed after ADV or PCV2 vaccination as well as after PCV2 natural infection due to restricted activation. Such results support the use of cytokine intracellular staining to monitor virus-specific cell-mediated immunity.     

Physiological effects of different Cd concentrations on maize root architecture and classification北大核心CSCD

In this research, a hydroponics experiment was conducted to apply different concentrations of cadmium (Cd) (0, 5, 10, 25, 50, 100, 200 μmol·L-1) to maize seedlings with two leaves and one new leaf, in order to explore the effects of the different Cd concentrations on the maize seedling growth, Cd absorption kinetics and root morphology and classification. After 5 days of Cd stress, the maize seedings were sampled, the plant height, main root length, aboveground and underground biomass, root architecture, Cd content and photosynthesis and related parameters were measured. It was found that with increasing Cd stress, the plant height, main root length, biomass and tolerance index of shoots and roots, total root length, root surface area, root volume, root forks and root tips all decreased significantly; Root average diameter and root:shoot increased significantly (P<0.05). Meanwhile root parameters (root length, root surface area and root volume) of root diameter classes designated Ⅰ-Ⅲ (0-1.5 mm) showed a decreasing trend, which had a significant (P<0.05) negative correlation with root Cd concentration. The proportion of root length, root surface area and root volume with diameter between 0-0.5 mm showed a downward trend under Cd stress. Under Cd stress, Cd concentration and accumulation in underground and aboveground parts of maize seedlings increased significantly, chlorophyll content decreased, and photosynthesis was inhibited. This study has shown that Cd affected root development mainly by inhibiting the growth and morphology of fine roots, and inhibited photosynthesis, elongation and biomass accumulation of the aboveground and underground parts of the maize seedings. © 2022, Editorial Office of Acta Prataculturae Sinica. All rights reserved.     

The Bolivian “Altiplano” and “Valle” sheep are two different peripatric breeds

Forty-nine sheep belonged to the Andean Altiplano region (“Altiplano”) and 30 in the lowland regions of Bolivia (“Valle”), aged 1 to 4 years, were wool sampled to determine the extent of difference between these local breeds. Fibre length and the percentage of each type of fibre (long-thick, short-thin and kemp), yield and fibre diameter were measured. There was a highly significant difference between the two sheep populations that were not clearly separated in the first two principal component of a principal components analysis (PC); the first PC explained 67.1 % and the second PC explained 26.6 % of the total variation. The variables that contributed most to the separation of the sheep populations were the percentage of long-thick and short-thin fibres in the first PC and yield in the second PC. A discriminant analysis, which was used to classify individuals with respect to their breeding, achieved an accurate classification rate of 84.2 %. Thus, the Altiplano and Valle sheep must be viewed as two closely peripatric breeds rather than different “ecotypes”, as more than 80 % could be correctly assigned to one of the breeds; however, the differences are based on composition of long-thick and short-thin fibres and yield after alcohol scouring.     

Methane emission of Santa Inês sheep fed cottonseed by-products containing different levels of gossypol

The aim of this study was to evaluate the methane (CH₄) emission of Santa Inês sheep fed cottonseed by-products, verifying if the gossypol content of these feedstuffs affects CH₄ emission. Twelve late-lactating Santa Inês sheep (44.8?±?7.5 kg body weight (BW)) were allocated in metabolic cages for an experimental period of 19 days, 14 days for adaptation and 5 days for measuring CH₄ emission and dry matter intake (DMI). The animals were divided into four treatments, established in accordance with the cottonseed by-product used in concentrate formulation: Control (CON - no cottonseed by-product), Whole cottonseed (WCS), Cottonseed cake (CSC), and Cottonseed meal (CSM). The free gossypol level of the concentrates were 0, 1,276, 350, and 190 ppm for CON, WCS, CSC, and CSM, respectively. Also, the animals received Cynodon dactylon cv. Coast Cross hay, water, and mineral salt ad libitum. The ether extract content of the diets was balanced between treatments by including soybean oil in concentrates. The technique used to measure the CH₄ emission was the sulfur hexafluoride (SF₆) tracer technique, and the gas samples collected were quantified by analysis in gas chromatography system. The CH₄ emission was evaluated considering the daily emission (g CH₄/day); DMI (g CH₄/kg DMI); and BW (g CH₄/kg BW). No statistical difference was found (P?>?0.05) between treatments for DMI and CH₄ parameters. In the regression analysis, no significant relation (P?>?0.05) between gossypol content and CH₄ emission was observed. These results suggest that gossypol does not affect rumen methanogenesis.     

Acid–base status and serum l-lactate in growing/finishing bull calves fed different high-grain diets

This study evaluated the influence of diet grain mix on the serum acid–base balance and productive performance of calves maintained on high-grain diets in a commercial feedlot system, monitoring progress over the entire 140-day productive cycle (i.e. both the growing and finishing periods). Thirty 14-week-old Belgian Blue bull calves were randomly allotted in equal numbers to one of three experimental groups defined by whether the cereal grain in their diet was predominantly corn (group C), predominantly barley (group B), or predominantly a mixture of corn and barley in approximately equal proportions (group CB). Blood pH, pCO₂, HCO₃^?, base excess and serum l-lactate were determined, as were several productive performance variables. The three groups differed significantly with respect to their weights at the end of the growing period (CB > C > B), but not in final weight; group B gained significantly more weight and had a lower daily intake than either group C or group CB during the finishing period. At no time during the study period was altered ruminal function suggested by either clinical signs or blood parameters, possibly because of the relatively high crude protein (CP) contents of the feeds and the use of barley straw as forage. Nevertheless, HCO₃^? and base excess were significantly higher in group C than in the other groups during the growing period, suggesting that supplementation of a high-CP corn-based diet with bicarbonate could lead to alkalotic blood base values (group C was the only group to receive bicarbonate supplement in this study). Also, in group CB HCO₃^? and base excess were generally lower than in the other groups during both the growing and finishing periods, much of the time exhibiting a falling trend compatible with the use of blood bases to counteract overproduction of ruminal acids; this behaviour, which may have been due to the lower dietary fibre content of the CB diet, does not support claims that diets with equal proportions of rapidly and slowly digested starch sources are more beneficial than those including only one of these starch source types. Serum l-lactate levels were almost invariably higher in group B than in group C, with group CB in between, in both the growing and the finishing periods; and a significant time × group interaction during the growing period suggests that the time course of serum l-lactate was determined mainly by the influence of diet on microbial growth rates in the rumen. Negative correlation between blood pH and pCO₂ around the switch between growing and finishing regimens suggests that diet may possibly modulate the influence of breed on pCO₂, but further is required to examine this hypothesis.     

Performance of layers reared and/or kept under different 6‐hour light‐dark cycles

1. Using 60 hens reared and kept on a standard lighting programme (decreasing followed by increasing photoperiod to 22 weeks of age and 14 h continuous light: 10 h continuous dark during lay) as control, the effects of the following intermittent patterns on development and performance were studied. Group 1. The same rearing programme, followed by, between 20 and 36 weeks, 3 h light (L) :3 h dark (D) intermittent and then from 36 weeks a regime in which each light period was progressively shortened by 30 min every 8 weeks with corresponding lengthening of the dark period so that the last cycle used between 52 and 60 weeks was 1.5 h L :4.5 h D. Group 2.6‐hour light‐dark cycles from hatching; the light: dark ratio first decreasing and then increasing, such that total light hours per day varied as in the control group to 20 weeks, and then subsequent lighting as in 1. Group 3. Intermittent lighting of 1.5 h L :4.5 h D unvaryingly from 4 to 60 weeks.

2. Sexual development was essentially the same in all groups. Egg numbers were decreased slightly by the short light‐dark cycles but daily egg mass output was the same in all groups. Food utilisation was best in group 1 and worst in the control group.

3. In general egg weight and shell quality were improved by the short light‐dark cycles; the effect appearing with the first eggs and being especially marked for group 3.

4. On intermittent regimes ovipositions were equally distributed between the four daily light‐dark periods when the light :dark ratio was near unity but were more numerous during the first half of the solar day when the ratio was 1.5 L:4.5 D.     

Research note: is starch utilization for fat deposition in man different from that in animals?

Utilization of starch for fat deposition in humans was investigated by means of the nitrogen-carbon-balance method in a respiration chamber using the difference principle with a basal and a supplemental period. The basal diet was designed to maintain an adequate energy balance of the volunteer and to meet the maintenance requirements of protein, minerals and vitamins. The dietary fat content was minimized to 2.7% of DM. The digestibility of starch energy was determined to be 97%. The estimated efficiency of ME utilization of starch for energy deposition in humans amounted to 75.8%, which was in accordance with former results in pigs and rats. This suggests that in case of an intake of diets rich in carbohydrates and low in fat the utilization of carbohydrates for lipogenesis in humans is similar to that in monogastric mammal animals.     

Prevalence of antimicrobial resistance among bacterial pathogens isolated from cattle in different European countries: 2002–2004

Background

The project "Antibiotic resistance in bacteria of animal origin – II" (ARBAO-II) was funded by the European Union (FAIR5-QLK2-2002-01146) for the period 2003–2005, with the aim to establish a continuous monitoring of antimicrobial susceptibility among veterinary laboratories in European countries based on validated and harmonised methodologies. Available summary data of the susceptibility testing of the bacterial pathogens from the different laboratories were collected.

Method

Antimicrobial susceptibility data for several bovine pathogens were obtained over a three year period (2002–2004). Each year the participating laboratories were requested to fill in excel-file templates with national summary data on the occurrence of antimicrobial resistance from different bacterial species.A proficiency test (EQAS – external quality assurance system) for antimicrobial susceptibility testing was conducted each year to test the accuracy of antimicrobial susceptibility testing in the participating laboratories. The data from this testing demonstrated that for the species included in the EQAS the results are comparable between countries.

Results

Data from 25,241 isolates were collected from 13 European countries. For Staphylococcus aureus from bovine mastitis major differences were apparent in the occurrence of resistance between countries and between the different antimicrobial agents tested. The highest frequency of resistance was observed for penicillin. For Mannheimia haemolytica resistance to ampicillin, tetracycline and trimethoprim/sulphonamide were observed in France, the Netherlands and Portugal. All isolates of Pasteurella multocida isolated in Finland and most of those from Denmark, England (and Wales), Italy and Sweden were susceptible to the majority of the antimicrobials. Streptococcus dysgalactiae and Streptococcus uberis isolates from Sweden were fully susceptible. For the other countries some resistance was observed to tetracycline, gentamicin and erythromycin. More resistance and variation of the resistance levels between countries were observed for Escherichia coli compared to the other bacterial species investigated.

Conclusion

In general, isolates from Denmark, England (and Wales), the Netherlands, Norway, Sweden and Switzerland showed low frequencies of resistance, whereas many isolates from Belgium, France, Italy, Latvia and Spain were resistant to most antimicrobials tested. In the future, data on the prevalence of resistance should be used to develop guidelines for appropriate antimicrobial use in veterinary medicine.