Epidemiology Of Influenza A Viruses In The Avian And Swine Populations In Peninsular Malaysia

Avian influenza (AI) that has emerged from animal reservoirs represents one of the greatest concerns to public health. To date, 16 hemagglutination subtypes and nine neuraminidase subtypes are found in many different combinations. The general objective of this study is to describe the epidemiology of influenza A viruses in the animal population in Malaysia. The specific objectives of the study are to describe the pattern and geographical distribution occurrence of the various AI strains in the avian species in Peninsular Malaysia based on retrospective examination of records and data from disease surveillance conducted in previous years, to identify, describe and determine the risk factors of the influenza strains circulating in the pig populations, and detect and isolate the influenza virus in the pigs, and molecularly characterised the strains that were isolated. A descriptive analysis was performed on the AI data based on the surveillance that was conducted by the Department of Veterinary Services (DVS) between 2000 to ii 2005. A three-page questionaire was developed and administered to the participating states. Only Kedah, Perak, Pulau Pinang, Johor, Negeri Sembilan and Pahang responded to the questionnaire. Data that were collected were compared to the total number of poultry farms and avian related establishments in each state. The sample size for each state was calculated using the formula given by Dahoo et al (2003) and using FreeCalc software. Using the assumptions of 0.5% prevalence and confidence level of 95%, neither highly pathogenic AI nor low pathogenic AI has been detected in samples.A cross-sectional study was carried out to determine the seroprevalence of H1N1 and H3N2 swine influenza virus (SIV) and the risk factors of SIV in the pig population. Between May and August 2005, 41 randomly selected farms were visited where a total of 727 serum samples from 4 to 6-months-old pigs were collected. Each subtypes of H1N1 and H3N2 were detected at 17 farms (41.4%). Eight-nine animals (12.2%) and 88 animals (12.1%) were seropositive for H1N1 and H3N2 respectively. Using binary logistic regression, four common risk factors were identified for SI H1N1 and H3N2: Farm size, farms that import pigs or purchase pigs from elsewhere, farms where animals such as cats were observed and farms that were closely located to another pig farm. The study proceeds with virus detection and isolation from randomly selected samples that were seropositive for H1N1 or H3N2. Allantoic fluids were collected from inoculated eggs and tested using hemagglutination test, One-Step Real time Polymerase Chain Reaction (RRT-PCR) and Conventional Reverse Transcriptase Polymerase Chain Reaction (RT-PCR). All samples were tested negative using HA and RRT-PCR. The failure to isolate the H1N1 and H3N2 viruses was possibly due to pigs that were not in the acute phase of the disease during the period when samples were collected, thus they did not shed the virus. The study found that a high percentage of pigs in Peninsular Malaysia were seropositive for H1N1 and H3N2. However, no isolates could be obtained to further characterise the virus to determine whether the virus strain was avian or human-related. This study revealed some of the deficiencies and issues with the existing disease surveillance that must be addressed to face the potential global influenza pandemic

Dietary Conjugated Linoleic Acid Alters Oxidative Stability and Alleviates Plasma Cholesterol Content in Meat of Broiler Chickens

This study was conducted to investigate the effects of dietary conjugated linoleic acid (CLA) on fatty acid composition, lipoprotein content, lipid peroxidation, and meat colour of broiler chickens. A total of 180 broiler chickens were allocated to 3 dietary treatments (0, 2.5, and 5% Lutrell) and given a standard broiler starter diet and finisher diet. Body weight of chickens and feed intake were recorded weekly. After slaughter, the breast meat was aged at 4°C for 0, 3, and 6 days. The fatty acid composition was measured in the breast meat. Body weight (BW) and feed efficiency were decreased by dietary CLA level (P<0.05). Chicken fed with 2.5% Lutrell had the highest feed intake compared to the control (CON) group. The total CLA increased significantly (P<0.05) in breast meat from birds supplemented with CLA. Propensity for lipid peroxidation was significantly higher after 6 days of meat storage (P<0.05) and the redness in chicken breast meat was lower in CLA-fed birds (P<0.05). It is also notable that a 5% Lutrell supplementation decreased the plasma total cholesterol (TC), low density protein (LDL), and HDL (high-density lipoprotein)/LDL ratio in chickens (P<0.05)

Upregulation of peroxisome proliferator-activated receptors and liver fatty acid binding protein in hepatic cells of broiler chicken supplemented with conjugated linoleic acids

Since conjugated linoleic acid (CLA) has structural and physiological characteristics similar to peroxisome proliferators, it is hypothesized that CLA would upregulate peroxisome proliferator-activated receptor (PPAR) and liver fatty acid binding protein (LFABP) in the liver of broiler chicken. The aim of the present study was to determine fatty acid composition of liver in CLA-fed broiler chickens and the genes associated with hepatic lipid metabolism. A total of 180-day-old broiler chicks were randomly assigned to two diets containing 0 and 2.5% CLA and fed for 6 weeks. Fatty acid (FA) composition of liver and PPAR α and γ and L-FABP were analyzed. It has been demonstrated that CLA was found in the liver of CLA-feed chicken compared to control group. Hepatic PPAR α and γ mRNA levels were upregulated 1.2 and 3-fold in CLA-fed chickens compared to chickens fed diet without CLA respectively. A similar response of upregulation was observed for L-FABP mRNA expression. Our data highlights the role of PPARs as a core regulator in the regulation of lipid metabolism in chicken liver

Effects of two herbal extracts and virginiamycin supplementation on growth performance, intestinal microflora population and fatty acid composition in broiler chickens

The competency of garlic and pennywort to improve broiler chicken growth and influence intestinal microbial communities and fatty acid composition of breast meat were studied. Two hundred forty, “day-old” chicks were randomly allocated to 4 treatment groups consisting of 6 replications of 10 chicks in each pen. The groups were assigned to receive treatment diets as follows: i) basal diet (control), ii) basal diet plus 0.5% garlic powder (GP), iii) basal diet plus 0.5% pennywort powder (PW) and iv) 0.002% virginiamycin (VM). Birds were killed at day 42 and intestinal samples were collected to assess for Lactobacillus and Escherichia coli. The pectoralis profundus from chicken breast samples was obtained from 10 birds from each treatment group on day 42 and frozen at −20°C for further analyses. Fatty acid profile of breast muscles was determined using gas liquid chromatography. Feed intake and weight gain of broilers fed with GP, PW, and VM were significantly higher (p<0.05) compared to control. Feeding chicks GP, PW, and VM significantly reduced Escherichia coli count (p<0.05) while Lactobacillus spp count were significantly higher (p<0.05) in the gut when compared to control group on day 42. Supplemented diet containing pennywort increased the C18:3n-3 fatty acid composition of chickens’ breast muscle. Garlic and pennywort may be useful in modulating broiler guts as they control the enteropathogens that help to utilize feed efficiently. This subsequently enhances the growth performances of broiler chickens

The effects of conjugated linoleic acid isomers on the morphological changes in adipose tissue and adipogenic genes expressions on primary adipose tissue

Previous studies carried out in mouse 3T3-L1 cell culture have shown that conjugated linoleic acid (CLA) inhibited adipocyte differentiation. The present study was undertaken to investigate the effect of cis-9, trans-11 and trans-10, cis-12 CLA isomers on morphological changes and on mRNA expressions in the in vitro adipocyte isolated from specific pathogen-free (SPF) chicken. The adipocytes were isolated from SPF chicken and cultured in differentiation-induction medium with different concentrations of cis-9, trans-11 and trans-10, cis-12 CLA. After day 7, the adipocyte differentiations were monitored morphologically and mRNA expressions of lipoprotein lipase (LPL) and acyl-coenzyme A binding domain containing 5 (ACBD 5) were quantified by real-time polymerase chain reaction (PCR) analysis. Our data suggested that cis-9, trans-11 CLA downregulated the expression of LPL and ACBD 5 genes, which was concurrently observed with decrease in the adipocyte area size and cell number compared to the control and trans-10, cis-12 treated groups. Based on this finding, we concluded that dietary CLA modulate fat reduction in chicken via alteration of transcription of key adipogenic genes and adipose cellularity

Effects of zinc oxide nanoparticles on growth performance and concentrations of malondialdehyde, zinc in tissues, and corticosterone in broiler chickens under heat stress conditions

The use of nanominerals, such as nano-zinc, represents a promising and emerging technology in the animal farming industry. Due to the small particle size and bioavailability of nano-zinc, it can be easily assimilated in the digestive system, thereby reducing excretion and environmental pollution. The present study was conducted to assess the effects of zinc oxide nanoparticles (ZnONPs) on the growth performance, zinc (Zn) concentration in edible tissues, thiobarbituric acid reactive substance, and corticosterone concentrations in broilers reared under normal or heat stress environmental conditions. The experiment was performed with a completely randomized design based on a 4 × 2 factorial arrangement consisting of 4 diets (basal diet + 60 mg/kg conventional zinc oxide as control diet; basal diet + 40 mg/kg of ZnONPs; basal diet + 60 mg/kg of ZnONPs; and basal diet + 100 mg/kg of ZnONPs) and 2 environmental conditions (normal and heat stress). On day 22, birds from each dietary group were divided equally to normal temperature (23 ± 1°C throughout) or heat stress conditions (34 ± 1°C daily for 6 h from 10:00 am until 4:00 pm). From 1 to 42 D of age, the broiler chickens fed 100 mg/kg ZnONPs exhibited lower feed intake and feed conversion ratio than the control. The accumulation of Zn in the liver of broilers was significantly higher among all treatment groups compared to breast and thigh muscle tissues regardless of the temperature conditions. At 40 and 60 mg/kg ZnONPs, the malondialdehyde content increased in thigh muscle of broilers at 7 D postmortem, indicating that ZnONPs potentially inhibited the antioxidant system in muscle tissues. The control and ZnONPs at 40 mg/kg and 60 mg/kg led to low serum corticosterone levels that may be attributed to the antioxidant and antistress properties of Zn. Taken together, although supplementation with ZnONPs at 40 mg/kg and 60 mg/kg alleviated the negative results of heat stress, further research is needed to determine the optimal level of dietary ZnONPs supplementation

Seroprevalence and risk factors for influenza a viruses in pigs in Peninsular Malaysia

Following a series of H5N1 cases in chickens and birds in a few states in Malaysia, there was much interest in the influenza A viruses subtypes that circulate among the local pig populations. Pigs may act as a mixing vessel for avian and mammal influenza viruses, resulting in new reassorted viruses. This study investigated the presence of antibodies against influenza H1N1 and H3N2 viruses in pigs from Peninsular Malaysia using Herdcheck Swine Influenza H1N1 and H3N2 Antibody Test Kits. At the same time, the presence of influenza virus was examined from the nasal swabs of seropositive pigs by virus isolation and real time RT-PCR. The list of pig farms was obtained from the headquarters of the Department of Veterinary Services, Malaysia, and pig herds were selected randomly from six of 11 states in Peninsular Malaysia. A total of 727 serum and nasal swab samples were collected from 4- to 6-month-old pigs between May and August 2005. By ELISA, the seroprevalences of swine influenza H1N1 and H3N2 among pigs were 12.2% and 12.1% respectively. Seropositivity for either of the virus subtypes was detected in less than half of the 41 sampled farms (41.4%). Combination of both subtypes was detected in 4% of all pigs and in 22% of sampled farms. However, no virus or viral nucleic acid was detected from nasal samples. This study identified that the seropositivity of pigs to H1N1 and H3N2 based on ELISA was significantly associated with factors such as size of farm, importation or purchase of pigs, proximity of farm to other pig farms and the presence of mammalian pets within the farm

Effects of Two Herbal Extracts and Virginiamycin Supplementation on Growth Performance, Intestinal Microflora Population and Fatty Acid Composition in Broiler Chickens

The competency of garlic and pennywort to improve broiler chicken growth and influence intestinal microbial communities and fatty acid composition of breast meat were studied. Two hundred forty, “day-old” chicks were randomly allocated to 4 treatment groups consisting of 6 replications of 10 chicks in each pen. The groups were assigned to receive treatment diets as follows: i) basal diet (control), ii) basal diet plus 0.5% garlic powder (GP), iii) basal diet plus 0.5% pennywort powder (PW) and iv) 0.002% virginiamycin (VM). Birds were killed at day 42 and intestinal samples were collected to assess for Lactobacillus and Escherichia coli. The pectoralis profundus from chicken breast samples was obtained from 10 birds from each treatment group on day 42 and frozen at −20°C for further analyses. Fatty acid profile of breast muscles was determined using gas liquid chromatography. Feed intake and weight gain of broilers fed with GP, PW, and VM were significantly higher (p<0.05) compared to control. Feeding chicks GP, PW, and VM significantly reduced Escherichia coli count (p<0.05) while Lactobacillus spp count were significantly higher (p<0.05) in the gut when compared to control group on day 42. Supplemented diet containing pennywort increased the C18:3n-3 fatty acid composition of chickens’ breast muscle. Garlic and pennywort may be useful in modulating broiler guts as they control the enteropathogens that help to utilize feed efficiently. This subsequently enhances the growth performances of broiler chickens

Response to dietary supplementation of L-glutamine and L-glutamate in broiler chickens reared at different stocking densities under the hot, humid tropical conditions

A study was conducted to determine whether supplementing AminoGut (a commercial dietary supplement containing a mixture of l-glutamine and l-glutamic acid) to broiler chickens stocked at 2 different densities affected performance, physiological stress responses, foot pad dermatitis incidence, and intestinal morphology and microflora. A randomized design in a factorial arrangement with 4 diets [basal diet, basal diet + 0.5% AminoGut from d 1 to 21, basal diet + 0.5% AminoGut from d 1 to 42, and basal diet + virginiamycin (0.02%) for d 1 to 42] and 2 stocking densities [0.100 m2/bird (23 birds/pen; LD) or 0.067 m2/bird (35 birds/pen; HD)]. Results showed that villi length and crypt depth were not changed by different dietary treatments. However, birds in the HD group had smaller villi (P = 0.03) compared with those of the LD group. Regardless of diet, HD consistently increased the serum concentrations of ceruloplasmin, α-1 acid glycoprotein, ovotransferin, and corticosterone (P = 0.0007), and elevated heterophil to lymphocyte ratio (0.0005). Neither AminoGut supplementation nor stocking density affected cecal microflora counts. In conclusion, under the conditions of this study, dietary supplementation of AminoGut, irrespective of stocking density, had no beneficial effect on growth performance, intestinal morphology, and physiological adaptive responses of broiler chickens raised under hot and humid tropical conditions. However, AminoGut supplementation from d 1 to 42 was beneficial in reducing mortality rate. Also, the increased serum concentrations of a wide range of acute phase proteins together with elevated corticosterone and heterophil to lymphocyte ratio suggested that high stocking density induced an acute phase response either indirectly as a result of increased incidence of inflammatory diseases such as foot pad dermatitis or possibly as a direct physiological response to the stress of high stocking density