Feeding antibiotics as growth promoters has had a substantial role in the poultry industry historically, although many countries now limit their use due to concerns over residues and microbial resistance in human medicine. For many years medicinal plants have been used as pharmaceuticals in natural therapy. However, limited studies have been conducted to investigate the effects of certain plants as feed additives in poultry. The importance and use of black pepper, cinnamon and turmeric is reviewed in the following paper. Black pepper acts as an antimicrobial, anti-inflammatory and antioxidant. Cinnamon has anti-allergenic, antioxidant, antifungal, anti-inflammatory, antiviral and blood purifying properties and aids in digestion. Turmeric acts as an antioxidant, anti-mutagenic, anti-inflammatory and antimicrobial agent and protects the liver against a variety of toxins. However, a systematic approach toward the efficacy and safety of these plant materials and their active compounds in poultry is still lacking.

The World’s Poultry Science Journal is indebted to Prof J.A. Castello, Prof D.K. Flock, Dr D. Grastilleur, Dr S. Cherepanov and Prof N. Yang for the translations of these summaries.

Following the removal of antibiotic growth promoters in animal feed, various products have been suggested as alternatives to the poultry feed industry. Among these products some types of clay or derivatives were used as a natural supply in order to optimise performance. Clay is indeed abundant naturally, cheap, widely used by hens raised outdoors voluntarily or by ingesting earthworms and soil fauna insects. As an indication it was estimated that a laying hen kept outdoors consumes 10g of soil, 7g of plant and 20g of insects and worms per day. In further studies it was reported that soil ingestion can reach 30% of dry matter intake. Considering their specific absorption capacities of ions, clays are considered real molecular sieves. Various studies have concluded that clays promote a hygienic digestive tract, increase food retention time and contribute to improving water retention and reducing the moisture content of droppings. The use of clays was accompanied by positive responses in nutrient digestibility, weight gain and feed conversion ratio. Also the addition of clay enhances meat sensorial value and organoleptic characteristics, the cutting yield and meat processing abilities. The antimicrobial and antitoxic properties of clay were shown to improve the appetite and weight gain of chickens eating food containing aflatoxins. In laying hens literature states that the use of clay improves egg size, egg internal qualities, shell strength and wet droppings. Clay use is also reported to reduce mite infestation in hens and improve ambient conditions in animal husbandry with substantially lower levels of NH3 and CH4.

The World’s Poultry Science Journal is indebted to Prof J.A. Castello, Prof D.K. Flock, Dr D. Grastilleur, Dr S. Cherepanov and Prof N. Yang for the translations of these summaries.