Comparative pharmacokinetics of orbifloxacin in healthy and Pasteurella multocida infected ducks

1. The pharmacokinetic aspects of orbifloxacin were studied in both healthy and naturally diseased ducks after a single intravenous and intramuscular dose of 5?mg?kg^?1 body weight. The serum concentrations of orbifloxacin following single intravenous and intramuscular injections were higher in diseased than in healthy ducks.

2. The disposition of orbifloxacin after a single intravenous injection was described by a two-compartment open model in both healthy and diseased ducks. Orbifloxacin was distributed and eliminated at a significantly slower rate in diseased than in healthy ducks. The total body clearance (Cl_B) was lower in diseased (0·131?l?kg^?1?h^?1) than healthy ducks (0·191?l?kg^?1?h^?1).

3. Following intramuscular administration of orbifloxacin, the peak serum concentration (C_max) was higher in diseased than in healthy ducks, and this was achieved at a maximum time (t_max) of 1·114 and 0·993?h, respectively. The drug was eliminated at a significant slower rate in diseased ducks (elimination half-life t _{0·5( el )?}=?5·07?h) than in healthy ducks (elimination half-life t _{0·5( el )?}=?4·18?h).

4. These results indicate that drug elimination patterns in healthy and diseased ducks are not the same. The pharmacokinetic profile of the drug is altered in diseased ducks due to the increased serum orbifloxacin concentrations compared with clinically healthy ducks. In conclusion, 5?mg?kg^?1 body weight of orbifloxacin administered as a single dose once daily could be useful in the treatment of disease caused by Pasteurella multocida pathogen in ducks.     

Effects of Saccharomyces cerevisiae extract on haematological parameters, immune function and the antioxidant defence system in breeder hens fed aflatoxin contaminated diets

1. The study was conducted to investigate the efficacy of Saccharomyces cerevisiae extract (SC) on haematological parameters, immune function, and the antioxidant defence system in breeder hens fed a diet contaminated with low level aflatoxin (AF).

2. Forty-eight Ross 308 breeder hens were fed on diets containing AF (0 or 100?µg/kg) and SC (0 or 1?g/kg) in a 2?×?2 factorial arrangement. Red blood cell (RBC), white blood cell (WBC), and platelet counts, differential leucocyte counts, blood CD3⁺, CD4⁺, CD8⁺ and CD5⁺ T cell ratios, phagocytic activity and oxidative burst of heterophils, plasma and liver catalase activity, and malondialdehyde (MDA) and ascorbic acid concentrations were measured.

3. Plasma and liver MDA concentrations increased (P?P?P?=?0·082) in hens fed the contaminated diet. WBC count, monocyte percentage, phagocytic activity and oxidative burst of heterophils increased (P?P?=?0.088) in SC extract supplemented hens. There was a significant interaction between AF and SC on heterophil, lymphocyte, CD5⁺ cell percentages, and plasma catalase activity. Blood heterophil percentage decreased but lymphocyte percentage increased in hens fed on the AF contaminated diet without SC supplementation. SC supplementation counteracted the negative effect of AF on heterophils and lymphocytes. The CD5⁺ cell percentage decreased in unsupplemented hens fed the AF contaminated diet and this negative effect was minimised in SC supplemented hens. Plasma catalase activity increased in SC supplemented hens fed the uncontaminated diet whereas the effect of SC decreased in hens fed the AF contaminated diet.

4. The SC reduced some of the some adverse effects of AF, and improved functions of the non-specific immune system. Therefore, the SC extract which has been used for improving productive performance in birds and mammals may also be useful for modulating some of the effects of a low level, chronic dosage of AF.     

The effects of phytase and root hydroalcoholic extract of Withania somnifera on productive performance and bone mineralisation of laying hens in the late phase of production

1. A 6-week study was conducted to investigate the effects of phytase and hydroalcoholic extract of Withania somnifera root (WS) on productive performance and bone mineralisation of laying hens in the late phase of production.

2. Diets were arranged factorially (3?×?2?×?2) and consisted of a positive control with adequate Ca (4·37%) and nonphytate P (NPP; 0·39%) and a negative control diet with Ca (4·06%) and NPP (0·36 %); three concentrations of Withania somnifera (0, 65 and 130?mg/kg diet); and two concentrations of microbial phytase (0 and 300 U/kg diet).

3. A total of 144 72-week-old Hy-Line W36 laying hens were randomly assigned to the 12 treatment groups. Each treatment was replicated 4 times (4 x 3 hens). Egg production and egg weight were recorded daily, while feed intake and egg quality traits were recorded every two weeks. Bone quality traits were evaluated at the end of experiment.

4. Withania somnifera supplementation increased egg production and lowered egg weight only in the second two weeks of the experiment. Addition of phytase significantly depressed specific gravity of the eggs for the entire experiment period. No dietary treatment effects were observed on egg shell thickness and yolk weight.

5. Withania somnifera at 130?mg/kg did not affect feed intake. The hens fed on the positive control diet had higher albumen weight than the negative control diet in the second two-week period. Supplementation of the positive control diet with 65?mg/kg Withania somnifera in the absence of phytase significantly improved shell weight compared with the negative control (5·779 vs. 5·273?g respectively).

6. Supplementing Withania somnifera significantly improved Ca and P retention in tibia bone. In addition, an increase in tibia bone P was observed with phytase supplementation. There were significant interactions between Withania somnifera content and phytase for tibia bone Ca and P.

7. The results of this experiment indicated that dietary Withania somnifera has beneficial effects on tibia bone Ca and P content, and phytase improved tibia bone P retention without adverse effects on productive performance.     

Evaluating the impact of excess dietary tryptophan on laying performance and immune function of laying hens reared under hot and humid summer conditions

1. Tryptophan (Trp), besides its role as an essential amino acid in protein synthesis, may also have other important effects on laying hens under summer conditions.

2. Babcock Brown layers (n?=?768), 40 weeks of age, were allocated to 4 treatment groups, each of which included 6 replicates of 32 hens. Each group received the same basal diet, formulated with maize and soybean meal, for 8 weeks. Hens were fed on the basal diet with 0·0, 0·2, 0·4, and 0·8?g/kg L-Trp to achieve dietary concentrations of 1·7, 1·9?g/kg, 2·1?g/kg or 2·5?g/kg of Trp, respectively.

3. Supplementing L-Trp had no affect on laying performance. Adding 0·2 or 0·4?g/kg L-Trp improved egg shell strength compared with those fed on the control diet. Serum albumin concentration increased at 0·4?g/kg compared with those receiving 0·0 or 0·8?g/kg Trp. The addition of Trp at 0·4?g/kg increased serum IgM concentration quadratically. Serum superoxide dismutase (T-SOD) increased linearly and quadratically at 0·4?g/kg.

4. In conclusion, we suggest that 0·2 to 0·4?g/kg Trp may have beneficial effects on laying hens under conditions of high temperature and humidity.     

The ostrich (Struthio camelus) ejaculate--effects of the method of collection, male age, month of the season, and daily frequency

1. Over three breeding seasons on a farm in Poland, semen was collected from 11 ostriches using the dummy and the teaser method to study the effects of the method of collection, male age, month in the breeding season, and daily collection frequency on ejaculate characteristics.

2. A total of 259 ejaculates were collected, with an average volume of 1·28?±?0·6 (±SEM) ml. Sperm concentration was 3·34?±?0·08?×?10⁹/ml, the total number of spermatozoa 4·32?±?0·22?×?10⁹, and motility 4·56?±?0·04.

3. There was no difference in ejaculates collected by the dummy and teaser methods, but the between-individual variation was considerable. Ejaculate characteristics increased with male age and varied between months, with little evidence for seasonal decline. Daily collections for 10 days did not affect sperm output.

4. The results open up avenues for further research on development of a viable protocol for artificial insemination in ostriches and efficient semen storage.

5. The between-male variation suggests that the ejaculate output could be maximized through selection.     

Ovarian morphology and internal vis-à-vis non internal laying in relation to triacylglycerol,hormones and their receptors concentration around the age of sexual maturity in broiler breeder hens

1. Ovarian morphology, serum hormone concentrations of 17-β-estradiol, progesterone, testosterone, tri-iodothyronine (T3), thyroxine (T4) and triacylglycerol (TAG) were investigated at 23 and 26 weeks of age in broiler breeder hens provided with ad libitum access to feed. Progesterone, oestrogen-β, thyroid-α and -β receptor mRNAs were also quantified in the infundibulum at the same ages.

2. A large variation in the ovarian morphology was observed at 23 weeks of age including hens with undeveloped ovaries, non-laying hens with post ovulatory follicles (POF) and a predominance of non-laying hens without a POF.

3. Serum concentrations of triglyceride, 17-β-estradiol and progesterone at 23 weeks of age were lower in hens with an undeveloped ovary compared with other groups of hens, whereas testosterone, triiodothyronine and thyroxin were higher.

4. At 26 weeks of age, the average number of hierarchical yellow follicles in normal layers was 7.64?±?0·41 whereas in internal layers, the follicular numbers were significantly greater at 8.66?±?0·53. The higher follicular numbers in internal layers were associated with higher serum triglyceride and progesterone concentrations.

5. Oestrogen receptor-β and thyroid receptor-β mRNA was up regulated in the infundibulum of internal layers compared with normal laying hens at 26 weeks of age.     

Pharmacokinetics of gatifloxacin in broiler chickens following intravenous and oral administration

1. The pharmacokinetics of gatifloxacin were investigated following intravenous and oral administration of a single dose at a rate of 10?mg/kg body weight in broiler chicks.

2. Drug concentration in plasma was determined using High Performance Liquid Chromatography with ultraviolet detection on samples collected at frequent intervals after drug administration.

3. Following intravenous administration, the drug was rapidly distributed (t_1/2α: 0·33?±?0·008?h) and eliminated (t_1/2β: 3·62?±?0·03?h; Cl_B: 0·48?±?0·002?l/h/kg) from the body.

4. After oral administration, the drug was rapidly absorbed (C _max: 1·74?±?0·024?µg/mL; T _max: 2?h) and slowly eliminated (t_1/2β: 3·81?±?0·07?h) from the body. The apparent volume of distribution (V_d(area)), total body clearance (Cl_B) and mean residence time (MRT) were 3·61?±?0·04?l/kg, 0·66?±?0·01?l/h/kg and 7·16?±?0·08?h, respectively. The oral bioavailability of gatifloxacin was 72·96?±?1·10 %.

5. Oral administration of gatifloxacin at 10?mg/kg is likely to be highly efficacious against susceptible bacteria in broiler chickens.     

Ventilation rates in large commercial layer hen houses with two-year continuous monitoring

1. Ventilation controls the indoor environment and is critical for poultry production and welfare. Ventilation is also crucial for assessing aerial pollutant emissions from the poultry industry. Published ventilation data for commercial layer houses have been limited, and are mostly based on short-term studies, mainly because monitoring airflow from large numbers of fans is technically challenging.

2. A two-year continuous ventilation monitoring trial was conducted at two commercial manure belt houses (A and B), each with 250?000 layers and 88 130-cm exhaust fans. All the fans were individually monitored with fan rotational speed sensors or vibration sensors. Differential static pressures across the house walls were also measured. Three fan performance assessment methods were applied periodically to determine fan degradations. Fan models were developed to calculate house ventilations.

3. A total of 693 and 678 complete data days, each containing >16?h of valid ventilation data, were obtained in houses A and B, respectively. The two-year mean ventilation rates of houses A and B were 2·08 and 2·10?m³?h^?1?hen^?1, corresponding to static pressures of ?36·5 and ?48·9?Pa, respectively. For monthly mean ventilation, the maximum rates were 4·87 and 5·01?m³?h^?1?hen^?1 in July 2008, and the minimum were 0·59 and 0·81?m³?h^?1?hen^?1 in February 2008, for houses A and B, respectively.

4. The two-year mean ventilation rates were similar to those from a survey in Germany and a 6-month study in Indiana, USA, but were much lower than the 8·4 and 6·2?m³?h^?1?hen^?1 from a study in Italy. The minimum monthly mean ventilation rates were similar to the data obtained in winter in Canada, but were lower than the minimum ventilation suggested in the literature. The lower static pressure in house B required more ventilation energy input. The two houses, although identical, demonstrated differences in indoor environment controls that represented potential to increase ventilation energy efficiency, and reduce carbon footprints and operational costs.     

Effects of dietary copper supplementation on production performance and plasma biochemical parameters in broiler chickens

1. A study was conducted to estimate the effect of copper (Cu) supplementation on growth performance and biochemical profiles of blood and meat in broiler chickens.

2. A total of 240?d-old broiler chicks (Vencobb-100) were randomly divided into 12 groups, each of 20 chicks (4 treatments?×?3 replicates).

3. The basal diet (T₁) contained 215?g?kg^?1 crude protein (CP), 12·76?MJ?kg^?1 ME, 32?g?kg^?1 total calcium and 5?g?kg^?1 total phosphorus. T_2, T₃ and T₄ were formulated to contain an additional 75, 150 and 250?mg?Cu?kg^?1 diet, respectively. Copper sulphate pentahydrate (CuSO₄, 5H₂O) was used as the source of Cu.

4. Significant reductions in plasma total cholesterol and triglyceride, and an elevated concentration of HDL-cholesterol, were observed in the chickens fed with 250?mg?Cu?kg^?1 (T₄) of feed at the 3rd and 6th week of the experiment. Total cholesterol in meat decreased significantly in the birds fed with dietary Cu at 250?mg?kg^?1 (T₄) of feed.

5. Growth performance was measured in terms of live weight gain, cumulative feed intake and feed conversion ratio at the end of d 21 and d 42 of the experiment, and the result was found to be commercially beneficial for the chickens receiving 150?mg?Cu?kg^?1 (T₃) of diet. The concentration of Cu in breast muscle and liver increased significantly at the end of experiment.

6. From this study it can be concluded that supplementation with dietary Cu may be beneficial for production performance and plasma biochemical characteristics of broiler chickens.     

Variation in amino acid digestibility of rapeseed meal studied in caecectomised laying hens and relationship with chemical constituents

1. The objectives were to study the variation in amino acid (AA) digestibility of rapeseed meal in laying hens and to investigate whether the variation in AA digestibility can be explained by chemical constituents of the rapeseed meal. Nine rapeseed meals from different processing plants operating in Germany were used. The crude protein and crude fibre concentrations of the meals ranged from 367 to 410 and 137 to 175?g/kg dry matter (DM), respectively. The concentrations of total glucosinolates varied between 5·1 and 12·9?mmol/kg DM. Each meal was included in one of the experimental diets at an inclusion level of 200?g/kg at the expense of maize starch.

2. A total of 16 Lohmann Brown laying hens were used for this experiment and were surgically caecectomised. They were housed individually in metabolism cages. Each of the 10 diets was fed to at least 6 hens in 4 periods of two weeks duration. Excreta were collected during the last 5?d of each period. The digestibility coefficient of AA was calculated for each diet. The digestibility of the rapeseed meals was calculated by multiple linear regression analysis.

3. Mean essential AA digestibility of rapeseed meals varied between 0·78 and 0·84. Among the essential amino acids, the highest level of digestibility was found for arginine (0·88) and methionine (0·87), and the lowest for lysine (0·74) and threonine (0·75). The highest variation between rapeseed meals in digestibility was found for threonine (0·68 to 0·79) and lysine (0·68 to 0·78). The concentration of neutral detergent insoluble nitrogen of the rapeseed meals was negatively correlated with the digestibility of lysine, but was not significantly correlated with digestibility of any other AA. Glucosinolate concentration was significantly correlated with valine digestibility.

4. Multiple regression analysis showed that the concentrations of crude protein and ash together were the major factors considered to explain variation in digestibility of essential AA. Additional consideration of neutral detergent insoluble nitrogen and total glucosinolates improved the goodness of fit only marginally and was unlikely to be of practical significance.     

Biotin intake and transfer to the egg and chick in broiler breeder hens housed on litter or in cages

1. Biotin concentrations in the plasma of hens and chicks and in egg yolk were measured at different ages in broiler breeder hens housed on litter or in cages and fed restricted amounts of diets containing different concentrations of biotin.

2. In the caged groups, biotin concentrations in these fluids increased with increasing maternal biotin intake over the range of intakes studied.

3. Biotin concentrations in hen plasma and yolk were linearly related and increased with age.

4. Biotin concentration in chick plasma was highly correlated (r = 0·93) with yolk concentration. The poorest biotin status was predicted for chicks from young hens.

5. There was no evidence that ingestion of excreta contributed substantially to the biotin status of hens housed on deep litter.

     

Pharmacokinetic analysis of cefquinome in healthy chickens

1. The pharmacokinetics of cefquinome (CEQ) in chickens was determined after intravenous (IV) and intramuscular (IM) administration of 2?mg/kg body weight. Plasma concentrations were measured by high performance liquid chromatography assay with an ultraviolet detector at 265?nm wavelength.

2. Plasma concentration–time data after IV administration were best fitted by a two-compartment model. The pharmacokinetic parameters following IV injection were distribution half-life 0·43?±?0·19?h, elimination half-life 1·29?±?0·10?h, total body clearance 0·35?±?0·04?l/kg/h, area under curve 5·33?±?0·55?µg/h/ml and volume of distribution at steady state 0·49?±?0·05?l/kg.

3. Plasma concentration–time data after IM administration were best described by a two-compartment model. The pharmacokinetic parameters after IM administration were absorption half-life 0·07?±?0·02?h, distribution half-life 0·58?±?0·27?h, elimination half-life 1·35?±?0·20?h, peak concentration 3·04?±?0·71?µg/ml and bioavailability 95·81?±?5·81%.

4. Cefquinome kinetics in chicken and data from other species were summarised and analysed to provide a comprehensive understanding of CEQ pharmacokinetics.     

Growth performance,carcass criteria,and serum biochemical parameters of broiler chickens supplemented with either synbiotic or prebiotic under hot climatic conditions

ABSTRACT

1. Two separate experiments were conducted to evaluate the efficacy of either prebiotic or synbiotic on growth performance, carcass yield, organ weights, and serum metabolic profile of broilers under hot climatic conditions.

2. In experiment 1, 150 1-d-old Ross 308 male broiler chickens were fed dietary synbiotic (Biomin® IMBO, 0, 1 or 1.5 g kg^?1 of the starter diets and 0, 0.5 or 0.75 g kg^?1 of the grower diets) for 6 weeks. In experiment 2, 150 1-d-old Ross 308 male broiler chickens were fed dietary prebiotic (Mannan oligosaccharide 0, 0.5 or 1 g kg^?1 of the starter diets and 0, 0.25 or 0.5 g kg^?1 of the grower diets) for 6 weeks. Each treatment had 10 replicates containing 5 broiler chickens each.

3. Supplementation of synbiotic at 1 or 1.5 g kg^?1 feed to broiler diets during 1–21 d and 0.5 or 0.75 g kg^?1 feed, respectively, during 22–42 d improved (P < 0.01) body weight gain, feed conversion ratio (FCR), and decreased (P < 0.01) abdominal fat, serum total cholesterol, and low-density lipoprotein (LDL) cholesterol levels in experiment 1.

4. Similarly, supplementation of the prebiotic at 0.5 or 1 g kg^?1 in broiler diets during 1–21 d and 0.25 or 0.50 g kg^?1 feed, respectively, during 22–42 d improved (P < 0.01) body weight gain, FCR, and decreased (P < 0.01) abdominal fat, serum cholesterol, and LDL-cholesterol levels in experiment 2.     

Egg production response of laying chickens to feather clipping,cool water and aspirin during hot weather conditions

An 8-week trial was conducted between March and May (hot-dry season) to determine effects of water temperature, feather clipping and aspirin on egg production of chickens. The treatments tested were hens given ordinary drinking water (control), cool water (100 g ice block per L) and aspirin (0.3 mg per L of ordinary water) and hens whose feathers were clipped (about two thirds of body feathers clipped). At 32 weeks of age, 120 Lohmann brown layer chickens of similar live weights were randomly divided into 12 groups of ten hens each and assigned to the treatments in triplicate using a completely randomized design. Feed and water were given ad libitum. Data included feed intake, water consumption, hen-day egg production and egg weight. Ambient house temperature, hen’s cloacal temperature and water temperature were monitored daily during the experimental period. Mean daily ambient temperature increased from 28.4 to 35.0 °C during the study period with consequent increase in cloacal temperatures (40.31 to 41.18 °C) of hens, ordinary drinking water and cool water. None of the treatments had any significant (P?>?0.05) effects on feed intake and water consumption of the birds. Hens given cool water produced more (P?P?P?>?0.05). It is concluded that the provision of cool water in a hot-dry climate had a beneficial effect on egg laying performance of chickens.     

Pharmacokinetics and bioavailability of valnemulin in Muscovy ducks (Cairina moschata)

1. A pharmacokinetic study of valnemulin was conducted in healthy Muscovy ducks after intravenous (IV), intramuscular (IM) and oral administrations at a dose rate of 15?mg/kg body weight.

2. Drug concentrations in plasma were determined by high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). Pharmacokinetics parameters of valnemulin were analysed by compartmental analysis using the WinNonlin program.

3. After IV administration, valnemulin was widely distributed with a volume of distribution based on a terminal phase (V_z) of 8·19?±?3·07?l/kg, a mean elimination half-life (t_1/2Ke) of 2·63?h, and a clearance (Cl) value of 5·56?±?1·53?l/kg/h. Following intramuscular and oral administration, valnemulin was rapidly absorbed; the C_max was 0·44?±?0·13 and 0·12?±?0·02?µg/ml (achieved at 0·28 and 1·80?h), the t_1/2Ke was 3·17?±?3·83 and 4·83?±?1·81?h, and the absolute bioavailability (F) was 72% and 37%, respectively.

4. The plasma profile of valnemulin exhibited favourable pharmacokinetic characteristics in Muscovy ducks, such as wide distribution, and rapid absorption and elimination, though oral bioavailability was low.     

Do stocking rate and a simple run management practice influence the infection of laying hens with gastrointestinal helminths?

The aim of this experiment conducted at four sites in Switzerland was to investigate the transmission and infectivity of the two main helminth parasite species of poultry (Ascaridia galli and Heterakis gallinarum) in outdoor runs with two different stocking rates. Additionally, the influence of a simple management practice (mowing of run) on helminth transmission was studied. Three run types were created on each site: runs C served as control (stocking rate 10 m²/hen, no management), runs B corresponded to runs C but were managed (10 m²/hen, management). In runs A stocking rates were doubled compared to control runs (5 m²/hen, no management). During two subsequent layer flocks, a set of parasitological parameters (faecal egg counts (FECs), prevalence, worm burdens in hens and in tracer animals, helminth eggs in soil) as well as parameters describing the run vegetation were determined. The increased stocking rate (runs A) led to a larger proportion of bare soil and to a reduction of the average vegetation height. In runs with a lower stocking rate (B and C), the proportion of bare soil did not increase during the experimental period. Irrespective of the run type, numbers of helminth eggs in the soil decreased significantly with an increasing distance to the hen houses, while the percentage of ground coverage as well as vegetation height increased. However, across runs the correlation between the percentage of ground cover and the values of eggs per gram soil between runs was very low (r² = 0.0007, P = 0.95) indicating a non-causal relationship. Significant differences in FEC were found in flock 2 (P < 0.001): FEC of hens in managed runs B were 24% lower (P < 0.05) than those of the control animals. Although not significant, the corresponding prevalence was lower (−9.7%) in hens from managed runs as well. Hens from runs with a high stocking rate (A) had significantly higher FEC than hens from control runs (C). In flock 2 management (n.s.) and higher stocking rates (−62%, P < 0.05) decreased the worm burdens. Tracer animals from runs with a high stocking rate (A) had significantly higher FEC than tracers from runs B and C in two tracer series. This was not reflected in the worm burdens. Overall, the stocking rate of hens in the outdoor run seemed not to influence the transmission patterns of A. galli and H. gallinarum and repeated mowing of runs did not reduce helminth infections. Lower stocking rates, however, led to a substantial improvement of the run vegetation.     

Propofol and fentanyl infusions in dogs of various breeds undergoing surgery

ObjectiveTo report the cardiovascular variables, anaesthetic effects and recovery quality of an anaesthesia technique using variable rate infusion propofol combined with constant rate infusion fentanyl in dogs undergoing elective surgery.Study designProspective clinical trial.AnimalsA total of 27 dogs, aged 2.7 ± 2.65 years and weighing 24 ± 11 kg.MethodsFollowing intramuscular acepromazine (0.03 or 0.05 mg kg^?1) and subcutaneous carprofen (4 mg kg^?1) pre-medication, anaesthesia was induced with propofol (4.0 ± 0.5 mg kg^?1) intravenously (IV). All dogs were ventilated with 100% oxygen to maintain normocapnia. Propofol was infused at 0.4 mg kg^?1 minute^?1 for 20 minutes and then at 0.3 mg kg^?1minute^?1. If mean arterial blood pressure (MAP) decreased below 70 mmHg, propofol infusion was reduced by 0.1 mg kg^?1 minute^?1. Five minutes after induction of anaesthesia, fentanyl was administered (2 μg kg^?1) IV followed by the infusion at 0.5 μg kg^?1 minute^?1 and atropine (40 μg kg^?1) IV. Heart rate, MAP, respiratory rate, tidal volume, end-tidal carbon dioxide, presence of reflexes, movements and recovery times and quality were recorded.ResultsMean anaesthetic duration was 131 ± 38.5 minutes. Mean heart rate peaked 10 minutes after atropine injection and gradually declined, reaching pre-anaesthetic values at 55 minutes. MAP easily was maintained above 70 mmHg. Mean times to return of spontaneous ventilation, extubation, head lift and sternal recumbency were 21 ± 10.1, 33 ± 14.6, 43 ± 19.7 and 65 ± 23.4 minutes, respectively. Recovery was smooth and quiet. The time to sternal recumbency was significantly correlated with the duration of anaesthesia and total dose of propofol; time to extubation was correlated to total dose of propofol.Conclusion and clinical relevancePropofol and fentanyl infusions provided stable cardiovascular function and satisfactory conditions for surgery. Some modifications of infusion rates are required to improve the long-recovery times.     

Egg production, egg quality and crop content of Rhode Island Red hens grazing on natural tropical vegetation

The aim of this experiment was to study the suitability of the outdoor system for Rhode Island Red hens under the tropical conditions of southern Mexico. Twelve floor pens, each containing four birds, were divided randomly into two groups. The first group was raised indoors only, while each of the second group replicates had access to an outdoor area with natural-grown vegetation from 0800 to 1700 hours daily. Both groups fed ad libitum on a commercial layers diet. The results revealed no differences in body weight between treatments. The outdoor group recorded significantly higher egg laying rate (86.90 vs. 78.05 %), higher egg mass (50.66 vs. 45.30 g egg/hen/day), and higher feed intake (103.70 vs. 97.67 g/day) versus the indoor group. The outdoor group had eggs with darker yellow yolks (9.46 vs. 5.46), lower yolk, and higher albumen proportions (P?<?0.05) versus the indoor group. The crop content of the outdoor hens consisted of 86.55 % concentrated feed, 6.30 % plant material, 2.27 % grit stones, 1.69 % snails and oyster shells, 1.25 % seeds, 0.95 % farm wastes, and 0.99 % insects, worms, and larvae. Of the outdoor hens, 43.1 % was observed to be in the range at each scanning time. The outdoor system in the tropics had beneficial effects on Rhode Island Red hen performance, and the hens utilized the outdoor area effectively and obtained various feed items.     

Head-cloaca controlled current stunning: assessment of brain and heart activity and meat quality

1. Behavioural and neural responses of 65 broilers to head-to-cloaca electrical stunning were evaluated and meat quality was assessed on two groups of 25 broilers stunned either head to cloaca, or in a conventional water bath method.

2. On the EEG recordings, a general epileptiform insult was observed when applying a current of 100?mA (100?Hz) or 70?mA (70?Hz) for 1·5?s. This general epileptiform insult shows a tonic, clonic and exhaustion phase followed by spikes of alpha, beta, theta and delta waves with duration of on average 34?±?12?s and 39?±?23?s respectively. These birds may have been unconscious for 20?s or longer, according to the correlation dimension analyses.

3. The heart rate decreased significantly (P? 4. Within a confidence limit of 95%, taking into account the number of animals with a reliable EEG, the chance of an effective stun of all broilers lies between 0·9 and 1·0?with a current of 70?mA (100?Hz for 1·5?s; n?=?28) and with 100?mA (100?Hz for 1·5?s; n?=?27).

5. The shear force of breast fillets was slightly lower (P? 6. It can be concluded that broilers are effectively stunned with the head-cloaca method by using a controlled current of 70?mA or 100?mA for 1·5?s. The fillets and legs of bird stunned head-cloaca showed fewer blood splashes in the muscles compared with birds stunned in a conventional water bath.     

Effects of dietary energy concentration, nonstarch polysaccharide concentration, and particle sizes of nonstarch polysaccharides on digesta mean retention time and gut development in laying hens

1. From an experiment with 504 laying hens (ISA Brown strain, 18–40 weeks of age), 90 40-week old hens were used for determining digesta mean retention time (MRT) and gut weight development. This experiment comprised 6 dietary treatments according to a 2?×?3 factorial design. Factors were dietary apparent metabolisable energy (AME) concentration (11·8 vs 10·6?MJ/kg), insoluble nonstarch polysaccharides (NSP) concentration (65 vs 134?g/kg), and fine vs coarse particle sizes of added NSP. Titanium recovery in different gut segments was used as an indicator of MRT.

2. Increasing NSP concentration prolonged MRT in the crop (68 vs 34?min) and total foregut (91 vs 57?min) compared with control NSP. Reducing energy concentration prolonged MRT in the colon (26 vs 7?min), and total hind gut (30 vs 9?min), compared with control energy. Overall MRT was not affected by dietary treatments.

3. Increasing NSP concentration increased relative weights of the empty proventriculus-gizzard and its contents by 30% (25·2 vs 19·4?g/kg) and 18% (15·4 vs 13·0?g/kg), respectively, compared with control NSP diets.

4. MRT in the foregut was prolonged as daily insoluble NSP intake increased, and this was more pronounced in hens given coarsely ground NSP, compared with finely ground. A prolonged MRT in the foregut seemed to indicate a higher level of satiety, which may contribute to a lower feather pecking pressure in laying hens.