First week nutrition for broiler chickens : effects on growth, metabolic status, organ development, and carcass composition

Abstract

During the first week of life, broiler chickens undergo various developmental changes that are already initiated during incubation. Ongoing development of organs such as the gastrointestinal tract and the immune system may affect the nutritional requirements during this age period. Despite the residual yolk that is available at hatch and that may provide nutritional support during the first days after hatch, the growth performance may be affected by the time in between hatch and first feed intake. Furthermore, it remains largely unknown to what extend nutritional composition of a pre-starter diet, as well as feed availability directly after hatch have an effect on physiological development directly after hatch, but also at later age. The aim of this thesis was to determine the impact of feed availability and feed composition provided during the first week of life on short-term physiological development, as well as potential long-term effects on growth performance of broiler chickens. Especially early hatched chickens were suggested to benefit more from direct feed access compared to midterm and late hatched chickens, as they tended to have a higher body weight gain during the first week after hatch. A delay in feed access for 48 h resulted in lowered body weight gain and feed intake when compared to direct feed access, but so did a short (13 to 26 h) delay in feed access after hatch. In the latter case, delayed feed access resulted in a lower weight to length ratio of the jejunum and ileum at 4 d of age compared with chickens with direct feed access. Although delayed feed access after hatch resulted in lower body weight gain during the first week after hatch and thereafter, it can be discussed whether this is truly an impairment of long-term growth or just a delayed onset of growth. With respect to feed composition, the inclusion of fish oil and medium chain fatty acids in a pre-starter diet had minor effects on humoral immune function. Inclusion of medium chain fatty acids did result in higher body weight gain and lowered feed efficiency during the first week of life, but only during the period it was provided. Feeding increased diet densities during the first week of life, obtained by formulating diets with different dietary fat levels, resulted in an increased gain to feed ratio, whereas body weight gain and feed intake decreased. Despite the shift in dietary energy supply from carbohydrates to fat and the perceived lower fat digestibility in young broiler chickens, nitrogen metabolizability and fat digestibility were not affected in the current study by feeding increased diet densities. The relative crop, liver and pancreas weights decreased when feeding increased diet densities, whereas the length of the entire intestinal tract increased. This suggests that broiler chickens repartition visceral organ development in response to feeding more concentrated diets during the first week of life. Interestingly, protein and fat accretion were not affected. Continued feeding of increased diet densities after ...

Induction of gut leakage in young broiler chickens fed a diet with low rye inclusion

“…The present model was able to induce gut leakage in young (14-day-old) broiler chickens, and it was not acute enough to affect older (28-day-old) chickens. Such a compensatory mechanism was previously demonstrated in broiler chickens (Maiorka et al, 2003;Santos et al, 2021) and might be an adaptive gut response after exposure to diverse sources of stress or dietary challenges (Lamot 2017). It is important to bear in mind that mRNA expression will not necessarily reflect the actual protein expression in tissue.…”

Effects of various levels of metabolizable energy in pre-starter diets of broiler chickens on growth performance

“…Moreover, in previous studies conducted on older birds, it was reported that there is a correlation between increasing energy density and decreased FI (10,23). According to Lemot et al (1), if the diet's energy density increases during the first week of a chick's life, the bird's ability to assimilate the nutrients in the food may be limited.…”

“…roiler chickens require a pre-starter diet during their first week of life to support growth and development due to their immature digestive system (1,2). Manipulating this diet can modify chicken development (3), but there is limited information on the effects of early nutrition and the composition of the pre-starter diet.…”

Cysteine in Broiler Poultry Nutrition

“…However, some authors [8,9] have suggested that other factors in combination with genetic make-up, such as nutrition, environment, age, sex, management, and health care, account for the successes achieved in managing dietary energy intake of broilers. Modern broilers perhaps eat to their physical capacity or adjust their feed intake in response to several factors including dietary energy [10], and increased nutrient density results in a linear improvement in weight gain and feed efficiency, without reduction in intake [11]. According to [12] constant intake of feeds high in protein and other nutrients increases supply of energy and results in a linear increase in protein accretion in tissues, until a maximum rate -a genetically defined term, is reached.…”