No abstract

The goal of this study was to determine the effects of feeding a zinc (Zn) deficient diet to broiler chicks for 96 h post-hatch followed by feeding diets with different Zn sources and supplemental levels (5 to 21 d) on the growth performance, tissue, and excreta Zn content. At the start of the study, four hundred 20-day-old male broiler chicks were divided into two groups. One group was fed a corn soybean meal based diet containing 25 mg of Zn/kg (imprinting diet, ID). The second group was fed the basal diet supplemented with 40 mg of Zn/kg from Zn oxide (ZnO) (non-imprinting diet, NID). Both groups were fed these diets for 96 h. At d 5, chicks from each group were randomly assigned to the dietary treatments consisting of the basal diet alone or the basal diet supplemented with 8 or 40 mg/kg Zn as ZnO or Zn proteinate. Main effects of post-hatch Zn ID were observed on feed intake and G:F. ID decreased (P < 0.05) feed intake and improved (P < 0.05) the gain to feed ratio (G:F) of 14 and 21 d old chicks compared to G:F of chicks fed NID. Additionally, G:F for 14 and 21 d was improved (P < 0.05) by interaction of Zn source × level. Furthermore, at d 21 chicks fed the ID had a lower (P < 0.05) Zn content in the tibia ash and excreta, and a higher (P < 0.05) Zn content in the pancreas tissue compared to chicks fed NID. These results suggest that Zn imprinting can affect body Zn stores and early performance.

The effects of manganese (Mn) preconditioning, 96 h post-hatch followed by the replacement of inorganic Mn with different levels of organic Mn (5 to 21 D), on growth, tissue excreta Mn content, gene expression, and enzyme activity were evaluated. A total of 420 day-old male Cobb 500 broilers were divided into 2 groups. One group was fed a corn–soybean meal basal diet containing 17 mg of Mn/kg (preconditioning diet, MnPD); the second group was fed the non-preconditioning diet (NPCD), which was the MnPD supplemented with 60 mg of Mn/kg from manganese sulfate (MnSO 4 ). On day 5, each group was divided into 5 subgroups and were randomly assigned to dietary treatments consisting of MnPD alone or MnPD supplemented with 12 or 60 mg Mn/kg Mn as MnSO 4 or Mn proteinate (6 replicate cages of 6 birds). Broiler chicks that were fed the MnPD had lower ( P ≤ 0.05) body weight gain (BWG) and G:F ratio when compared to those that were fed the NPCD for 4 D. Birds that were fed MnPD (1 to 4 D) and switched to MnPD supplemented with 60 mg/kg Mn (5 to 21 D) had lower ( P ≤ 0.05) BWG compared to those that were fed NPCD (1 to 4 D) and switched to MnPD supplemented with 60 mg/kg Mn for 21 D. Excreta, tibia ash, liver, and heart Mn levels were increased ( P ≤ 0.05) by supplemental Mn. The expression of jejunum divalent metal transporter-1 mRNA levels, as well as activities of plasma total super oxide dismutase and liver alanine transaminase, was not affected by MnPD or Mn source and levels. These results confirmed that feeding marginally deficient Mn diets to broiler chicks post-hatch does affect growth rate and tissue Mn concentration.

SummaryInorganic trace mineral salts in the premix have a detrimental effect on the stability of vitamins due to redox reactions. A study was conducted to investigate the effect of dietary supplementation of different levels of vitamin premix with different mineral premixes on the performance and bone characteristics of broilers. A 2 x 2 factorial dietary treatment was used with two levels of vitamins and two types of minerals in the premix. A total of 1056, one-day old chicks were randomly assigned to four dietary treatments with 12 replicate pens of 22 chicks for 28 d. An interactive effect between vitamin levels and mineral sources on weight gain and feed intake of chickens was detected. Chickens fed the diet containing 100% vitamin premix with either source of mineral premix had higher (P &lt; 0.01) weight gain and feed intake than those fed the diet containing 30% vitamin premix with either source of mineral premix. However, the chickens fed the diet containing the 30% vitamin premix with the organic minerals had higher (P &lt; 0.01) weight gain and feed intake than those fed the diet containing 30% vitamin premix with inorganic minerals. Chickens fed the diet containing organic mineral premix had lower (P &lt; 0.05) mortality and feed to gain ratio and higher (P &lt; 0.01) bone breaking strength and ash content of tibia than those fed the inorganic mineral premix treatment. Chickens fed the diet containing 100% vitamin premix had higher (P &lt; 0.01) breaking strength of femur and tibia ash than those fed the diet containing 30% vitamin premix. The results from this trial indicated that total replacement of inorganic trace minerals with organic minerals can increase the storage stability of vitamins in feed premixes containing both vitamins and trace minerals, which is reflected in better growth performance in poultry.

SummaryThe oxidation (rancidity) of fat is a very common feed quality issue, which can negatively affect growth performance and meat quality of broilers. Besides other factors, metal ions such as Zn, Cu and Fe can facilitate lipid peroxidation in feed. The objective of the current study was to investigate the effect of feeding corn soy diets containing fresh or oxidised soybean oil with different forms of microminerals on production performance of broiler chicks. Dietary treatments consisted of a 2 × 2 factorial structure with two kinds of soybean oil (oxidised or fresh) and two forms of microminerals (inorganic or organic). Mineral proteinate (Bioplex®, Alltech Inc.) including Zn, Mn, Cu and Fe was used as the organic source and was supplemented at the level equivalent to 25% of an inorganic source in the control diets. Organic selenium (Sel-Plex®, Alltech Inc.) at 0.3 mg/kg of diet was used to replace sodium selenite used at 0.3 mg/kg of diet in control diet. Oxidised soybean oil was prepared by convection heat (90°C for a period of seven days in a convection oven). A total of 1152 one-day old chicks were allotted randomly to the four dietary treatments using 12 replicates of 24 chicks per pen. Chicks were raised in floor pens for 42 days in an environmentally controlled room with free access to feed and water. There was no statistical interaction between oil source and mineral form on performance or mineral content of breast meat. Feeding oxidised oil increased (P < 0.05) feed intake and decreased gain to feed ratio (FCE) of chicks. Supplementation with organic minerals improved (P < 0.05) weight gain and FCE of chicks. The breast meat of chicks fed organic mineral had higher (P < 0.01) Se content than those from the control group. The results indicated that the addition of organic minerals to broiler diets can minimise the negative impact of oxidised oil on the performance of broiler chicks.

The present study evaluated the blood gas and electrolyte balance in broiler chicks fed with diets containing different levels of vitamin premix (VM) and forms of trace minerals. VM was included at 30 or 100% of commercial levels. Trace minerals were provided as either inorganic (IOM) or organic trace minerals (OTM). This experiment, which used one-day-old male broiler chicks, featured a factorial treatment structure with four treatments using 12 replicate pens (22 chicks/pen), each arranged in a randomised complete block design. An i-STAT® handheld, point-of-care, clinical analyser, loaded with blood gas, lactate and electrolyte cartridges, was used to analyse blood samples. Significant interactions for vitamin levels and mineral form were observed for bicarbonate, base excess, total carbon dioxide, ionised calcium and haematocrit levels. Using OTM, but not IOM, in the premix resulted in blood gas and electrolyte values that were comparable to those in 100% VM-fed group. The consumption of 30% VM reduced pO2 (P<0.01), sO2 (P<0.01), pH (P=0.05) and K+ with concomitant increases in lactate, glucose and Na+ (P<0.03). However, OTM tended to reverse the Na+ effect (P=0.05) along with higher partial CO2 (P<0.05). These results demonstrated the negative effects of a 30% VM diet on blood gas and electrolyte balance, which triggered nutritionally induced metabolic acidosis. However, metabolic acidosis induced by underfeeding VM (30%) was restored or normalised by using OTM, but not IOM, in the vitamin-mineral premix.