WHO ProDuction CARES... In any phase of the pig’s life, proper nutrition will improve health. The ‘Alltech pig advantage’ programme is no exception. With decades of dedicated research, the ‘Alltech pig advantage’ programme can help improve immunity, weight gain, and meat quality. alltech ad So, who cares about your customer’s profit? Remember Alltech (Pty) Ltd | PO Box 7156 | Stellenbosch | 7599 | South Africa Tel: (021) 865 2669 | Fax: (021) 865 2673 | www.alltech.com ...if your customer needs some tasty returns? As the swine industry returns to profitability, are you switching from “survivor” mode to “driver” mode and making sure you’re maximising profitability? DOES! www.facebook.com/AlltechNaturally www.twitter.com/@Alltech Copyright, ©, 2011, Alltech. All rights reserved 32 Porcus October/November 2011 Porcus Augustus/September 2010 32
nutrition More awareness of mycotoxins By Dr H.V.L.N. Swamy, Alltech Canada The immediate challenge chemists around the world face are related to masked mycotoxins and the means and modes of analysing them so that their masked effects can be quantified. In this article, demonstrated effects of the key mycotoxins on swine health and performance are highlighted, while referencing to their regional distribution. Mycotoxins are the secondary metabolites of moulds, which are ubiquitous in nature. There are close to 500 mycotoxins that have been identified to date, and undoubtedly there are many more to come. Four genera of mycotoxin producing moulds on a global scale include Aspergillus, Fusarium, Penicillium and Claviceps. As for mycotoxins, harmful to swine health and performance, the group includes aflatoxins, ochratoxins, Type A trichothecene Fusarium mycotoxins, Type B trichothecene Fusarium mycotoxins, fumonisins, zearalenone, and ergot alkaloids. Classifying the mycotoxins to a specific region has been curtailed in recent years due to the extended trading of grains and meals across the world as well as appreciable changes in the global climatic conditions. Unexpected drought, rainfall and floods added more mystery to the already complex issues of sampling and mycotoxin analysis. Nevertheless the greater prevalence of a specific group of mycotoxins to a particular region can be generalised. Comparative toxicity Unlike poultry, the information on systematic comparative toxicity of mycotoxins in pigs is not available. Based on the literature information available and field experience, the severity of key mycotoxin toxicities on pig performance (weight gains or reproduction) can be ranked as: Aflatoxins (400 ppb) > Deoxynivalenol (DON, 1 000 ppb) > Zearalenone (around 1 000 ppb) > Ochratoxins (1 000 to 2 000 ppb) > T- 2 toxin (3 000 ppb) > Fumonisins (10 000 ppb). It is worth mentioning that these observations were made assuming that individual mycotoxin was present without appreciable levels of other mycotoxins. Although aflatoxins are more toxic to pigs, their presence at such levels is uncommon. On the other hand, although fumonisins are least toxic among these mycotoxins, their presence at 10 000 ppb or even more can be a common phenomenon in corn. Toxicity of some mycotoxins The biggest challenge with mycotoxicoses is the non-specific nature of symptoms in the affected animals. As compared to poultry, the acute symptoms are relatively more specific in pigs at least for some of the most common mycotoxins. These can include zearalenone-induced reproductive disorders (hyperemic and enlarged vulva), fumonisins-induced pulmonary odema and DON-induced feed refusal. The effect of low levels of mycotoxins on immunity of pigs can still go unnoticed and this makes it very hard for swine producers to diagnose the issue and take subsequent prevention measures. The symptoms of mycotoxicoses, such as lowered feed intake, can also be due to poor management, nutrition and health. It is quite common under commercial conditions, therefore, to compare the mycotoxin results of swine feed with the symptoms on the farm to confirm mycotoxicoses. Acute and chronic toxicities of some of the important mycotoxins in swine are discussed here. In general, the toxicity of mycotoxins mainly depends on the dose and source of mycotoxins, and the duration of exposure. Aflatoxins Meissonnier and others (2005) recently reviewed aflatoxicosis in swine. Aflatoxin B 1 (AFB 1 ) is the most toxic followed by AFG 1 , AFB 2 and AFG 2 . During acute aflatoxicosis in swine, almost all animals die within hours or days following the intoxication. During chronic aflatoxicoses, the first signs are significant reductions in feed intake and a depressed state of the animals. AFG 1 can induce more severe liver pathology in pigs than AFB 1 and both when present together can result in additive interaction. AFB 1 concentration of 400 ppb seems to be the minimum concentration in feed to cause performance problems in pigs, however, the immunity can be compromised at levels as low as 280 ppb. Chronic intoxication with aflatoxins reduce vaccine efficacy. Aflatoxins alter inflammatory reactions via inhibiting the normal functioning of macrophages, neutrophils and NK cells as well as through modulating cytokine production. The effect of aflatoxins on antibody production is not consistent while its effect on cell mediated immunity, especially lymphocyte proliferation, is well documented in pigs. Association of aflatoxins with other mycotoxins does not seem to induce synergic toxic effects except for fumonisin B 1 (FB 1 ). At higher concentrations (around 800 ppb), AF can affect reproductive efficiency of pigs and AFB 1 and AFM 1 residues can be detected in sow milk. Ochratoxins Although the ochratoxin group comprises seven compounds, onlyochratoxin A (OA) has been foundwidespread as a natural contaminant ofcereal grains. OA mainly affectsprotein synthesis and subsequently DNA and RNA synthesis. Kidneys are the major target organs for ochratoxins and as a result of kidney damage the animals increase their water consumption. Similar to aflatoxins, these groups of toxins are carcinogenic and can be detected in animal products, especially pork. The residual levels of ochratoxins in pork are highly regulated in some of the European countries. Ochratoxins can reduce weight gain, feed intake and feed efficiency in pigs and can impair kidney function at levels as low as 500 ppb. There have been efforts to consider serum and kidney concentrations of OA as the biomarker for animal exposure. OA can reduce cellmediated immunity of pigs and can delay the response to immunisation. Obviously this can lead to increased susceptibility of pigs to natural infectious diseases. Feeding OA to boars can reduce motility and longevity of spermatozoa. Type A trichothecene Fusarium mycotoxins The toxicity of these mycotoxins in swine has been recently reviewed by Meissonnier and others (2008). Their target organs mainly include the rapidly dividing cells lining gastrointestinal tract, the skin, and lymphoid and erythroid system. Although they are more toxic than type B trichothecene mycotoxins, their occurrence is sporadic. Pigs can be acutely exposed to T-2 toxin via oral, inhalation or topical routes. Death following acute Continued on p 34 Porcus January/February 2012 33
Change language