In vivo immunomodulatory effects of plant flavonoids in lipopolysaccharide-challenged broilers.

Plant flavonoids are generally regarded as natural replacers of synthetic growth promoters in poultry production. This study investigated the immunomodulatory effects of plant flavonoids, such as genistein and hesperidin, in lipopolysaccharide (LPS)-challenged broilers. A total of 700 21-day-old commercial Arbor Acres broiler chicks were randomly assigned into six treatment groups, each having six pens of 20 chicks/pen. Chicks were fed a basal diet without any additive (control, CON), 5 mg genistein/kg feed (G5), 20 mg hesperidin/kg (H20), or a basal diet with a combination of genistein and hesperidin (1 : 4) with doses of 5 mg/kg feed (GH5), 10 mg/kg (GH10) and 20 mg/kg (GH20) for 6 weeks. Half of the birds from each treatment were separated, and either challenged with 0·9% sodium chloride solution or Escherichia coli LPS (250 µg/kg BW) on days 16, 18 and 20. The results showed that both genistein and hesperidin improved (P<0.01) the plasma antioxidant status of growing broilers, by increasing total antioxidant capacity (TAOC), superoxide dismutase (SOD) activity and decreasing malondialdehyde production. LPS challenge further increased (P<0.05) TAOC and SOD levels. Regardless of LPS challenge, both genistein and hesperidin improved the humoral and mucosal immunity by increasing the intestinal intraepithelial lymphocyte numbers (P<0.01), as well as anti-Newcastle disease and anti-avian influenza antibody titers (P<0.05). Supplementation of both the plant flavonoids generally increased (P<0.05) the immune organs indices (spleen, thymus and bursa). Thus, supplementation of basal diet of broiler chicks, either with genistein or hesperidin, improved immune and antioxidant status of growing broilers. In addition, combined supplementation of both the flavonoids showed further improvement than individual compounds.

Effects of genistein and hesperidin on biomarkers of heat stress in broilers under persistent summer stress.

This study investigated the supplemental effects of the flavonoids genistein and hesperidin for biomarkers of heat stress in broilers reared under persistent summer stress. A total of 360 one-day-old, mixed-sex broiler chickens were divided into 6 treatment groups: control or supplemented with 5 mg of genistein•kg of feed(-1), 20 mg of hesperidin•kg of feed(-1), or a mixture of genistein and hesperidin (1:4) at a dosage of 5 mg•kg(-1), 10 mg•kg(-1), and 20 mg•kg(-1) of feed. Broilers were slaughtered at 42 d and samples were analyzed for hematological profile, creatine kinase, lactate dehydrogenase, and heat shock protein 70 mRNA levels. Results showed that dietary genistein and hesperidin improved (P < 0.05) the weekly performance of broilers particularly during the finisher period. The circulating heterophils and heterophil-to-lymphocyte ratios were found to decrease (P < 0.01) in the treated groups. Moreover, biomarkers of heat stress including the level of creatine kinase, lactate dehydrogenase, and heat shock protein 70 mRNA of breast muscle was also changed (P < 0.01) positively by the dietary compounds with pronounced effects of combined treatments. These findings suggested that genistein and hesperidin could be a prime strategy to ameliorate summer stress effects in broilers; and a combination of both compounds may lead to mutual synergistic effects. It could be suggested that dietary use of both genistein and hesperidin as a feed supplement may offer a potential nutritional strategy in tropical and subtropical regions to overcome the deleterious effects of persistent summer stress in broiler production.

Two splice variants of the bovine lactoferrin gene identified in Staphylococcus aureus isolated from mastitis in dairy cattle.

Bovine lactoferrin (bLF) is a member of the transferrin family; it plays an important role in the innate immune response. We identified novel splice variants of the bLF gene in mastitis-infected and healthy cows. Reverse transcription-polymerase chain reaction (RT-PCR) and clone sequencing analysis were used to screen the splice variants of the bLF gene in the mammary gland, spleen and liver tissues. One main transcript corresponding to the bLF reference sequence was found in three tissues in both healthy and mastitis-infected cows. Quantitative real-time PCR analysis showed that the expression levels of the LF gene's main transcript were not significantly different in tissues from healthy versus mastitis-infected cows. However, the new splice variant, LF-AS2, which has the exon-skipping alternative splicing pattern, was only identified in mammary glands infected with Staphylococcus aureus. Sequencing analysis showed that the new splice variant was 251 bp in length, including exon 1, part of exon 2, part of exon 16, and exon 17. We conclude that bLF may play a role in resistance to mastitis through alternative splicing mechanisms.