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.     

真武汤口服液对肉鸡腹水综合征预防效果的试验研究

肉鸡腹水综合征(Ascites Syndrome,AS),又称肺动脉高压综合征,是一种以右心肥大和腹腔内积聚大量浆液性淡黄色液体为特征的营养代谢性疾病[1-3]。Maxwell对世界五大洲20多个养禽国进行了调查和统计分析,认为肉鸡AS在世界范围内的发病率为4.2%,每年约有70亿只肉鸡遭受此病的侵害     

Pharmacokinetics and oral bioavailability of pentoxyfylline in broiler chickens

The pharmacokinetic properties of pentoxyfylline and its metabolites were determined in healthy chickens after single intravenous and oral dosage of 100 mg/kg pentoxyfylline. Plasma concentrations of pentoxyfylline and its metabolites were determined by a validated high-performance liquid chromatographic method. After intravenous (i.v.) and oral (p.o.) administration, the plasma concentration-time curves were best described by a one-compartment open model. The mean elimination half-life (t(1/2el)) of pentoxyfylline was 1.05 h, total body clearance 1.90 L/h x kg, volume of distribution 2.40 L/kg and the mean residence time was 2.73 h, after i.v. administration. After oral dosing, mean maximal plasma concentration of pentoxyfylline was 4.01 microg/mL and the interval from p.o. administration until maximum concentration was 1.15 h. The mean oral bioavailability was found to be 28.2%. Metabolites I, IV and V were present in chicken plasma after both i.v. and p.o. administration, with metabolite V being the most dominant.     

The oral bioavailability of ibuprofen enantiomers in broiler chickens

Doses of racemic ibuprofen ranging from 5 to 20 mg/kg body weight were administered intravenously (i.v.) and orally to broiler chickens and plasma concentration-time profiles for both ibuprofen enantiomers were determined. The absorption of ibuprofen was evaluated after a bolus administration of a commercially available suspension into the crop and proventriculus, respectively. An enterohepatic circulation as described for other nonsteroidal anti-inflammatory drugs (NSAIDs) in other species could be suggested for both enantiomers after i.v. and oral administration. Significantly higher area under the curve (AUC) values for S(+)-ibuprofen compared with R(-)-ibuprofen were collected after crop and proventriculus administration. Several factors could be responsible for the significant differences in AUC values between both enantiomers.     

Effects of sex,age and food intake upon metabolisable energy values in broiler chickens

1. Nitrogen‐corrected apparent metabolisable energy (AME_n) values of 2 diets with different energy: protein ratio were estimated in an experiment with 8 groups of female and 8 of male chickens in 15 sequential 3‐day balance periods from the 12th to the 56th d of age.

2. The effect of sex on AME_n values was not significant.

3. The effect of age was highly significant. AME_n values of the mixture with the narrower energy: protein ratio increased with age. The dependence of AME_n of the diet with the wider energy: protein ratio on age was parabolic, AME_n values increasing only until the 37th day of life.

4. Under conditions of ad libitum feeding, AME_n of the mixture with the wider energy: protein ratio given to female chickens decreased significantly with increasing food intake.     

Toxicokinetics and absolute oral bioavailability of melamine in broiler chickens

The objective of this study was to investigate the toxicokinetic characteristics of melamine in broilers due to the limited information available for livestock. Melamine was then administered to broiler chickens at an intravenous (i.v.) or oral (p.o.) dosage of 5.5 mg/kg of body weight, and plasma samples were collected up to 48 h. The concentration of melamine in each plasma sample was analyzed using liquid chromatography‐tandem mass spectrometry (LC‐MS/MS). Melamine was measurable up to 24 h after i.v. and p.o. administration. A one‐compartment model was developed to describe the toxicokinetics of melamine in broilers. Following i.v. administration, the values for the elimination half‐life (t_1/2β), the volume of distribution (V_d), and the clearance (CL) were 4.42 ± 1.02 h, 00.52 ± 0.18 L/kg, and 0.08 ± 0.01 L/h/kg, respectively. The absolute oral bioavailability (F) was 95.63 ± 3.54%. The results suggest that most of the administered melamine is favorably absorbed from the alimentary tract and rapidly cleared by the kidneys in broiler chickens.     

Determination of artemisinin in Artemisia sieberi and anticoccidial effects of the plant extract in broiler chickens

Artemisinin has received much attention in the treatment of malaria in recent years, and it is now considered as a potential candidate to reduce coccidial infection in chickens. It is a sesquiterpene compound which has been isolated from Aretemisia annua for the first time. The present study aimed to investigate the occurrence of artemisinin in A. sieberi (AS) and to test the anticoccidial effects of plant extract in broiler chickens. The aerial parts of the plant were collected during different seasons from Yazd Province, in the centre of Iran. The artemisinin content of the AS was extracted with petrol ether and analysed by high-performance liquid chromatography using UV detection. Anticoccidial effects of the plant extract were tested on chicks challenged with various species of Eimeria. The infected chickens were treated with doses of 1 or 2.5 mg/kg per day artemisinin via oral administration of plant extract. The analytical results showed that the level of artemisinin in AS was 0.2% and 0.14% of dried weight (DW) of plant materials in summer and autumn, respectively. Treatment of experimentally infected chickens with AS extracts showed that artemisinin was able to reduce the severity of coccidial infection induced by Eimeria tenella and E. acervulina, but not E. maxima. The anticoccidial effects of artemisinin were shown by significant decrease in output of number of oocysts per gram of faeces in chickens challenged with different species of Eimeria. This study showed that the levels of artemisinin in AS were comparable with those in other species including A. annua, and that the extract of this plant can reduce coccidial infection in broiler chickens.     

Pharmacokinetics of sanguinarine,chelerythrine, and their metabolites in broiler chickens following oral and intravenous administration

Sanguinarine (SA) and chelerythrine (CHE) are the main active components of the phytogenic livestock feed additive, Sangrovit®. However, little information is available on the pharmacokinetics of Sangrovit® in poultry. The goal of this work was to study the pharmacokinetics of SA, CHE, and their metabolites, dihydrosanguinarine (DHSA) and dihydrochelerythrine (DHCHE), in 10 healthy female broiler chickens following oral (p.o.) administration of Sangrovit® and intravenous (i.v.) administration of a mixture of SA and CHE. The plasma samples were processed using two different simple protein precipitation methods because the parent drugs and metabolites are stable under different pH conditions. The absorption and metabolism of SA following p.o. administration were fast, with half‐life (t_1/2) values of 1.05 ± 0.18 hr and 0.83 ± 0.10 hr for SA and DHSA, respectively. The maximum concentration (C_max) of DHSA (2.49 ± 1.4 μg/L) was higher that of SA (1.89 ± 0.8 μg/L). The area under the concentration vs. time curve (AUC) values for SA and DHSA were 9.92 ± 5.4 and 6.08 ± 3.49 ng/ml hr, respectively. Following i.v. administration, the clearance (CL) of SA was 6.79 ± 0.63 (L·h^?1·kg^?1) with a t_1/2 of 0.34 ± 0.13 hr. The AUC values for DHSA and DHCHE were 7.48 ± 1.05 and 0.52 ± 0.09 (ng/ml hr), respectively. These data suggested that Sangrovit® had low absorption and bioavailability in broiler chickens. The work reported here provides useful information on the pharmacokinetic behavior of Sangrovit® after p.o. and i.v. administration in broiler chickens, which is important for the evaluation of its use in poultry.     

Selection of foods by broiler chickens following corticosterone administration

1. The effects of corticosterone (CORT) on diet selection of broiler chickens offered a choice of a high protein concentrate (381 g CP/kg, 17.5 MJ/kg ME) and whole wheat (113 g CP/kg, 15.9 MJ/kg ME) in relation to age were examined in two experiments.

2. Daily intramuscular injections of 2 and 4 mg/kg of CORT for a 5‐d period in both 2‐ and 5‐week‐old chickens resulted in increases in total food, protein and energy intakes. This led to a decrease in protein accretion in older but not younger chicks, an increase in total lipid contents of the carcase at both ages, and produced changes in internal organs.

3. CORT significantly reduced body weight gain of young but not old chickens, suggesting that mature birds respond better than young ones to the physiological changes caused by treatment, by making subsequent appropriate food choices.

4. Administration of CORT in young chicks increased wheat intake at 2 and 4 h after injection, while in older birds a similar increase was maintained up to 24 h after injection. Intake of HP food was decreased by both doses of CORT in young chicks but there was no significant effect in older chickens.

5. Changes in energy: protein ratio in the chosen diet appeared at 4 h after treatment in old chickens and at 24 h in younger chicks.

6. The results suggest that birds are able to detect metabolic changes caused by CORT administration and attempt to redress them by modifying their food pattern. The time course of the response of birds to these changes is age related. However, the food selection pattern did not completely compensate for the physiological defects.     

Pharmacokinetics and oral bioavailability of sulfadiazine and trimethoprim in broiler chickens

Sulfonamides and trimethoprim are chemotherapeutics that are extensively used in various animal species. Little information about the pharmacokinetics of these compounds in chickens exists in the literature. In this study, a new commercial formulation of sulfadiazine in combination with trimethoprim was administered both intravenously and orally, according to a crossover design, to healthy, 7-week-old broilers. The plasma concentrations of the drugs were determined by validated high-performance liquid chromatographic methods, and pharmacokinetic parameters were calculated. After intravenous or oral administration of trimethoprim (6.67 mg/kg body weight) and sulfadiazine (33.34 mg/kg body weight), both active substances were rapidly eliminated from the plasma. There was a mean half-life of 1.61 h for trimethoprim and 3.2 h for sulfadiazine. The apparent volumes of distribution (2.2 and 0.43 L/kg, respectively, indicated that the tissue distribution of trimethoprim was more extensive than that of sulfadiazine. The oral bioavailability was approximately 80% for both components.     

Linkage between the intestinal microbiota and residual feed intake in broiler chickens

Background: Intestinal microbiota plays a key role in nutrient digestion and utilization with a profound impact on feed efficiency of livestock animals. However, the intestinal microbes that are critically involved in feed efficiency remain elusive.Methods: To identify intestinal bacteria associated with residual feed intake(RFI) in chickens, male Cobb broiler chicks were individually housed from day 14 to day 35. Individual RFI values were calculated for 56 chickens.Luminal contents were collected from the ileum, cecum, and cloaca of each animal on day 35. Bacterial DNA was isolated and subjected to 16 S rRNA gene sequencing. Intestinal microbiota was classified to the feature level using Deblur and QIIME 2. High and low RFI groups were formed by selecting 15 and 17 chickens with the most extreme RFI values for subsequent LEfSe comparison of the difference in the microbiota. Spearman correlation analysis was further performed to identify correlations between the intestinal microbiota composition and RFI.Results: No significant difference in evenness, richness, and overall diversity of the microbiota in the ileum, cecum,or cloaca was observed between high and low RFI chickens. However, LEfSe analysis revealed a number of bacterial features being differentially enriched in either high or low RFI chickens. Spearman correlation analysis further identified many differentially enriched bacterial features to be significantly correlated with RFI(P 0.05). Importantly,not all short-chain fatty acid(SCFA) producers showed a positive association with RFI. While two novel members of Oscillibacter and Butyricicoccus were more abundant in low-RFI, high-efficiency chickens, several other SCFA producers such as Subdoligranulum variabile and two related Peptostreptococcaceae members were negatively associated with feed efficiency. Moreover, a few closely-related Lachnospiraceae family members showed a positive correlation with feed efficiency, while others of the same family displayed an opposite relationship.Conclusions: Our results highlight the complexity of the intestinal microbiota and a need to differentiate the bacteria to the species, subspecies, and even strain levels in order to reveal their true association with feed efficiency. Identification of RFI-associated bacteria provides important leads to manipulate the intestinal microbiota for improving production efficiency, profitability, and sustainability of poultry production.     

早期限饲对肉仔鸡的影响

遗传育种选育和营养水平的改进,在使肉仔鸡生长速度不断提高的同时带来了一系列负面影响,如脂肪沉积、代谢性疾病、骨骼疾病、死亡率增加。早期限饲在改善这些问题上有一定的作用。本文综述了早期限饲对肉仔鸡的生产性能和健康状况等影响,并对早期限饲的进一步研究方向进行了展望。     

Effect of decreased feed intake on serum and pancreatic alpha-amylase of broiler chickens

Removal of feed from 20-day-old broiler chicks for 24 hours caused serum and pancreatic alpha-amylase activities to increase almost twofold. A 24-hour feeding period following feed removal caused a reduction in serum alpha-amylase to basal levels and a sixfold reduction in pancreatic alpha-amylase activity. Serum alpha-amylase levels remained elevated after long-term feed restriction in adult broilers compared with levels in full-fed controls. Reduction in feed intake in chicks caused by coccidial infections also resulted in increased serum alpha-amylase. In all cases, the degree of change in serum alpha-amylase corresponded inversely to feed intake. It is proposed that the pancreas synthesizes a specific quantity of alpha-amylase, which does not change even under conditions of extended underconsumption of feed. The rate of alpha-amylase secretion is determined, at least indirectly, by the rate of carbohydrate metabolism, and the remainder of the enzyme is stored in the pancreatic cells. A small percentage of the stored enzyme diffuses into the blood and thus directly reflects increased secretion or accumulation of alpha-amylase in the pancreas in response to conditions of carbohydrate utilization.     

Swollen-head syndrome in broiler chickens

Swollen-head syndrome is a disease seen in broiler chickens between 4 and 6 weeks of age in Southern Africa. It appears to be caused by a mixed coronavirus and Escherichia coli infection. The coronavirus appears to be of a hitherto unrecorded serotype. The disease is controlled by an attenuated live-virus vaccine and antibacterial medication.     

Salt poisoning in broiler chickens

The clinical signs of salt poisoning in young chickens are thirst, diarrhoea and weakness. When 13 500 broilers are simultaneously affected, the deterioration that occurs in their physical condition and in the litter beneath their feet is dramatic. Two flocks of meat chickens on a small unit in North Otago were affected in this way.