Securing carcass quality with minerals

04-09-2015 | | |
Good carcass quality is imperative for healthy birds and effective processing.
Good carcass quality is imperative for healthy birds and effective processing.

Over the last 5 years broiler carcass ?prices remained below 1.8 euro/kg and cut prices were stagnating ranging from 1 to 2.5 Euro/kg of carcass. Good carcass quality has become a minimum ?requirement for trading and a constant focus on preventing downgrading is imperative. Trace element ?supplementation in feed can help.

Some grading systems exist for broiler chicken carcasses. In the European Union, grading includes mainly two categories. They include a level of nonconforming carcasses that cannot exceed 16.6% for grade A (good quality) and 33% for grade B (intermediate quality). Scoring criteria of broiler chicken carcasses are related to the following parameters. They have to be intact including the presentation, clean and free from visible foreign matter but also from foreign smell. They should also be free of visible bloodstains except those which are small and unobtrusive, of protruding broken bones and of severe contusions. In some countries, attention is also given to disjointed bones. The quality of blood vessels, the strength of bones and tendons are therefore becoming targets to improve broiler carcass grading. The two major pathologies dealing with bone strength and tendons are tibial dyschondroplasia and perosis. They are known to impact negatively animal performance due to lameness prevalence and this makes them even more important to control. These two pathologies have been partly related to nutritional issues which, still today include trace mineral supply. Tibial dyschondroplasia, perosis pathologies and the trace minerals deficiencies known to be involved in the disease will be described hereafter.

Tibial dyschondroplasia

Tibial dyschondroplasia has been described as a disease in which growth plate cartilage accumulates in the metaphyseal region of the tibiotarsus. This disease is associated with fast growing animals and the lesions can regress with increasing age. Of the different criteria identified that induce the disease, the most known is copper deficiency. The most stringent proof of copper implication in disease modulation is that diets deficient in copper have been successfully used to produce tibial dyschondroplasia lesions in experimental models.

Some deficiencies in other trace elements such as zinc were also shown to inhibit chondrocyte (cartilage cell) proliferation and to increase their apoptosis in broilers. The lesions induced by zinc deficiency were similar to the ones observed during tibial dyschondroplasia. Research indicated that most of the trace elements are able to intervene in bone formation as they act as co-factors of different specific enzymes involved in the process. The zinc acts through its effect on protein and nucleic acid metabolism, as a cofactor of alkaline phosphatase or collagenases, or through the modification of the crystalline structure of apatite (bone mineral matrix). He also wrote that copper acts as a cofactor of the lysyl-oxidase and enzyme which control the regulation of collagen and elastin fibre reticulation. The manganese acts as a cofactor of glycosyltransferase which is implicated in the formation of glycosaminoglycane containing chondroïtine sulphate and in the synthesis of the proteoglycanes present in the conjugating cartilage of avian epiphysis. This indicates that these trace elements can potentially reduce tibial dyschondroplasia occurrence through bone formation strengthening.


Perosis symptoms are enlargement of the tibio-metatarsal joint, bending of the distal end of the tibia and the proximal end of the metatarsus and displacement of the Achilles tendon. Locomotion is impaired and in severe cases the animal is unable to stand. Some trace mineral deficiencies have been identified as one of the possible causes of perosis. As an example, the omission of manganese in diets resulted in a depressed growth rate and an increase in the incidence and severity of bone abnormality. Doses of 55 mg/kg manganese as MnCl2 decreased perosis incidence. Already in 1938, it was observed that perosis was associated with a decrease in phosphatase activity in both blood and bones.

A reduction of these two pathologies has a direct impact on broiler carcass quality grades. In addition some specific carcass parts such as paws have gained some economical interest. In fact, the revenue from chicken paws in 2008 alone was worth $ 280 million in the US. In 2012, their mean price was set at 13.67 $ /kg making it the third most important chicken export revenue. Paw quality is becoming an important economic issue.



Paw quality

Paw quality is reduced when the animals are subject to footpad dermatitis problems. Footpad dermatitis is defined as: “a type of contact dermatitis affecting the plantar region of the feet in poultry and other birds. At an early stage, discolouration of the skin is seen. Hyperkeratosis and necrosis of the epidermis can develop, and in severe cases, these changes are followed by ulcerations with inflammatory reactions of the subcutaneous tissue.” Footpad dermatitis looks to be the consequence of a myriad of interacting factors but litter moisture appears to be the most likely culprit. Even if trace mineral deficiencies have not been considered a the main factor of footpad dermatitis occurrence, several trials looking at trace elements supplementations and more specifically organic sources have shown that trace mineral supplementation can reduce footpad dermatitis occurrence. It is well known from the field that trace element sources can behave differently.

Securing carcass quality

Except for paw quality, trace element deficiencies have been clearly identified as a source of the diseases. Providing a trace element source that is recognised to be highly bioavailable in several animal species such as B-TRAXIM 2C would improve animal trace mineral status and reduce the occurrence of deficiencies. The final consequence is the reduction of pathologies, which have been related to trace element deficiency such as tibial dyschondroplasia and perosis. For example, some trace element sources have shown to be more efficient as an enzyme co-factor than others. A numerical increase in alkaline phosphatase levels was observed in rats fed B-TRAXIM 2C Zn compared to ZnSO4.

These results indicate that B-TRAXIM 2C Zn would probably be more efficient than a sulphate source in reducing the incidence of perosis in Zn deficient animals and therefore limit carcass down grading. In the cases, where the pathology has not been related to trace element deficiencies such as footpad dermatitis, a comparison of different trace element sources is necessary. One trial available with B-Traxim 2C Zn and Mn is showing some footpad scoring reduction. The first treatment consisted in the combination of inorganic sources of Zinc and Manganese at high doses (160 g/t Zn as ZnO and 72 g/t of Mn as MnSO4: Inorganic). The second treatment was a combination of Zn and Mn from B-TRAXIM 2C at reduced doses (44 mg/kg Zn as B-TRAXIM 2C Zn and 42 mg/kg Mn as B-TRAXIM 2C Mn: B-TRAXIM 2C). The two treatments were compared for footpad scoring following the scoring system presented in the Figure 1.

On week 6, 50% of the broilers from the B-TRAXIM 2C group presented no sign of footpad dermatitis. On the contrary, more than 40% from the inorganic group broilers already exhibited some large footpad dermatitis scoring. The subsequent week, the footpad dermatitis status of the broilers evolved with more than 80% of the broilers subject to large footpad lesions. Even if a small evolution was observed in the B-TRAXIM 2C group, the broilers were distributed between the 5 scores nearly equally between 15 and 25% of occurrence. These results show that B-TRAXIM 2C Mn and Zn inclusion in broiler diets can have some beneficial impacts on footpad dermatitis.

Using B-TRAXIM 2C in order to reduce these three pathologies influencing broiler lameness and final carcass grading can be beneficial to reduce financial associated losses. In addition to the products effectiveness to reduce lameness and associated carcass quality defaults, B-TRAXIM 2C can also be used to improve the overall income from the carcass with some modifications in the carcass cuts proportions. A trial performed in Israel, on 384 Ross male broilers, replaced the total supply from inorganic trace element source by their corresponding B-TRAXIM. The supplemented levels of Cu, Fe, Mn and Zn were set at 15, 40, 100 and 100 ppm, respectively. This made the overall concentration in trace elements much higher than the NRC requirements for all trace elements except for Iron.

Even though no differences could be observed on overall animal performance, there were some interesting results related to the supplementation of B-TRAXIM to these broilers on carcass quality and carcass cuts. Some highly significant effects could be observed on the dressing percentage or drumsticks percentage of these broilers. These results indicate that total replacement of inorganic sources by B-TRAXIM 2C can favour some of the cuts proportions and give some additional incomes for slaughter houses and/or integrators. In the same study, the productivity index was calculated for both treatments. The results show that the production index was increased by 6.4% for animals fed with organic minerals.

Safe and solid use of OTM

With Zinc and Copper deficiencies known to induce tibial dyschondroplasia or Manganese deficiencies known to induce perosis, trace element deficiencies can definitely impact negatively locomotion but also carcass quality of broiler chickens. Providing B-TRAXIM 2C instead of other source can reduce the negative impact of these deficiencies as it has shown its better bioavailability in several animal species. B-TRAXIM 2C Zn is more efficient than Zinc sulphate in promoting alkaline phosphatase activity which makes it a good supplement for animals subject to perosis. B-TRAXIM 2C has shown its ability to reduce footpad dermatitis occurrence. B-TRAXIM 2C can improve carcass quality through cut proportions modification and provide additional incomes for integrators and slaughter houses. Several studies show that it is not only possible to improve the bioavailability of minerals but also to expect a strong return on investment and concrete benefits for end-users.

References available upon request.

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Ionescu Ewenn Helary Pancosma