Cristina Lima

1. IntroductionPhytogenic feed additives (PFA) are the plant derived products used to improve performance of livestock and poultry (Windisch et al., 2008; Jacela et al., 2010). The PFA comprise of a wide variety of herbs, spices and products derived thereof and are mainly essential oils. This class of feed additives is at present used to a great extent as alternatives to the antibiotic growth prom ...

I. INTRODUCTIONForecasting is fraught with difficulties associated with poor data and unknown unknowns. Fortunately, in the case of laying hens, this is not true. We have an excellent history of how our birds have improved over the past decade (Table 1), and a fair idea of what can be expected in future breeding programmes used by the primary breeding companies. Our understanding is that the requi ...

IntroductionAdvances in genetics has certainly produced commercial strains of poultry and pig with greater performance (e.g. growth, reproduction) with minimal feed input. For example, over the last 5 decades, the body weight of broilers at 42 days has increased by 25-50 g per year and the feed conversion ratio to 2 kg body weight has improved 2-3 points annually (Havenstein et al., ...

Recently, many studies have been investigating the impact of antibiotics on the gut microbiota, and researchers have shown that, in addition to altering the composition of the microbiota, antibiotics also can affect the gene expression, protein activity and the overall metabolism of the intestinal microbiota. Microbial changes caused by antibiotics, increase the immediate risk of infection and can ...