In vitro Evaluation of Acaricidal Efficacy of Selected Essential Oils against Dermanyssus gallinae

Intensification of poultry production has been associated with an increase in parasite prevalence and adaptation of an invasive external parasitic species, such as the poultry red mite (Dermanyssus gallinae). The studies of biological efficacy (contact and fumigant) and level of toxicity to mites indicated that the external application of essential oils (EOs) can be an alternative to acaricides. In this study, the results of acaricidal efficacy of eight selected EOs - Lavandula angustifolia Mill., Laurus nobilus L., Mentha x piperita L., Mentha spicata L., Ocimum basilicum L., Salvia officinalis L., Satureja montana L. and Thymus vulgaris L. are presented. Their chemical profiles were analyzed by gas chromatography coupled with mass spectrometry (GC–MS). The acaricidal efficacy of EOs (6% concentration) was tested on adult mites over 10 days in laboratory conditions using the Petri-dish method, through direct exposure for 1 min (contact toxicity) and subsequent exposure for 1 h (residual toxicity). The most effective EO in direct exposure-contact, after 48 h of observation, was S. montana (100% toxicity), while the greatest residual effect was observed in T. vulgaris (11% toxicity). The obtained results showed high efficacy of the EOs against the mites through direct contact and thus their great acaricidal potential. However, the activity was lost with subsequent exposure, indicating the absence of prolonged effect. Possible ways to overcome this problem are discussed further in this paper. In any case, the present study confirmed the acaricidal potential of herbal medicines that can be used in the integrated control of poultry red mite

Conjugated linoleic acids in poultry nutrition

Конјуговане линолне киселине (CLA) су позициони и геометријски изомери есенцијалне линолне масне киселине. У исхрани људи CLA имају антиканцерогено, антиатерогено, имуномодулаторно и деловање против гојазности. Такође повољно утичу на имуни систем, метаболизам костију и односе ткива у телу. Највеће количине CLА налазе се у месу преживара као последица активности бактерија (Butirovibrio fibrisolvens) које изомеризују линолну киселину. Садржај CLА не разликује се само између врста меса (говеђе, овчије, свињско, живинско), већ и између различитих ткива исте животињске врсте. Исхрана има значајан утицај на садржај CLА у ткивима животиња. Бројне студије су показале да се садржај CLА може повећати како код преживара, тако и код моногастричних животиња. Код моногастричних животиња садржај CLА може да се повећа њеном употребом у исхрани или додавањем у оброк животиња њених прекурсора (вакценска киселина, омега-7 масна киселина). У исхрани живине, препарати CLА додају се најчешће у количини до 2%, што повећава садржај CLА у месу и при том не утиче негативно на производне резултате и параметре квалитета меса. Запажено је да повећан садржај CLА у месу повoљно утиче на његову оксидативну стабилност. Основни циљ употребе CLА у исхрани живине је повећање садржаја CLА у месу, чиме може да се добије производ посебног квалитета (функционална храна).Conjugated linoleic acid (CLA) are positional and geometric isomers of essential linoleic fatty acid. CLA in the human diet have anti-carcinogenic, anti-atherogenic, immunomodulatory and anti-obesity functions. Also, they have a beneficial effects on the immune system, bone metabolism and interrelation of tissues in the body. The highest amounts of CLA have been found in meat of ruminant as a result of bacterial activity (Butirovibrio fibrisolvens) which have the capacity to isomerise linoleic acid. The content of CLA is not different only between various types of meat (beef, sheep, pork, poultry) but also between different tissues of the same animal species. Nutrition has a significant impact on the content of CLA in animal tissue. Numerous studies have shown that content of CLA can be increased in the ruminants such as in monogastric animals. In monogastric animals the content of CLA can be increased by their use in food or by adding in animal meal their precursors (vaccenic acid, an omega-7 fatty acid). In poultry nutrition CLA preparations are usually added in an amount up to 2%, which increases the CLA content in meat without any adverse effect on the performance and meat quality parameters. It was observed that increased content of CLA in meat favorably affect its oxidative stability. The main objective of the use of CLA in poultry nutrition is to increase the CLA content in meat in order to obtain a product of a special quality (functional food)