The 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 aim of this review paper is to update, present and discuss the current research findings from recent studies regarding the efficacy of organic sources of microelements in poultry nutrition. Most intensively evaluated in poultry feeding studies have been organic forms, i.e., proteinates and amino acids complexes and chelates, of such microelements as Zn, Mn and Cu. The results of these studies are not always consistent, particularly in regard to performance indices; however, the majority of the findings from recent experiments indicate that organic minerals are an effective source of microelements, and can replace, with some advantages, inorganic forms of minerals in poultry diets. One of the main benefits is the option to use lower inclusion levels of minerals added in organic forms, which may reduce the mineral content in the resulting poultry excreta.

Trace minerals are an essential part of poultry diets, even though the trace mineral requirements recommended by the NRC (1994) for poultry are based on very limited research work. For poultry producers, mineral salts are routinely over-formulated to ensure adequate levels are fed and requirements are met. This practice has caused concerns regarding optimising the genetic potential of modern breeds and environmental pollution. In recent years, extensive research work has been carried out to compare organic mineral sources, such as proteinates or amino acid chelates, with inorganic forms in poultry diets. This paper reviewed the research results conducted globally to date with mineral proteinate (Bioplex®, Alltech Inc, USA) including Zn, Cu, Mn and Fe. These replicated trials have used broilers, pullets and laying hens of different ages and in various practical raising conditions such as cages and floor pens. The main findings include: 1) mineral proteinate has a higher retention rate and relative bioavailability value than reagent grade inorganic salts; 2) the antagonism between minerals such as Zn and Cu could be avoided by using organic forms; 3) supplementing high levels of Cu or Zn as inorganic salt in poultry diets negatively affected the efficacy of phytase in the diet, which could be overcome by using mineral proteinate; 4) the replacement of inorganic minerals with lower level organic forms can support the optimal performance of broilers and layers and minimise the impact of minerals on the environment.

A trial was conducted using 134 pigs from weaning (21 kg) to finishing (105 kg) fed wheat-soy based commercial feeds formulated with either inorganic minerals or lower levels of organic (chelated) forms. Pigs fed the organic mineral diet has significantly higher (P < 0.05) average daily gain (ADG) compared to those receiving the inorganic control diet between day 31 and 64 of the trial period. The pigs receiving the organic minerals yielded 2 kg extra carcass weight, higher slaughter efficiency (P < 0.05) and greater ham width (P < 0.05). Economic benefits resulted for the organic mineral diets, due to improved performance and reduced mineral inclusion.