Can we feed mycotoxin contaminated feed to pigs?

Posted in: Prairie Swine Centre by admin on January 1, 2008 | No Comments

Deoxynivalenol (DON) is a mycotoxin produced by fungi which may contaminate cereal grains, including barley and wheat. The contamination is especially problematic when wet, warm conditions prevail during the growing season. The ingestion of grain that is severely contaminated by DON will cause overt symptoms such as vomiting (hence the common name “vomitoxin”). Less dramatic, but more frequently observed symptoms, reduced feed intake and growth, will result when pigs consume feed with a lower concentration of the mycotoxin. The Canadian Feed Inspection Agency suggests that 1 ppm mycotoxin in feed is a safe upper limit for swine.

There are several feed additives available which reportedly reduce the impact of the mycotoxin on the pig. Modes of action vary, and include; binding the mycotoxin in the gut and preventing absorption, chemically transforming the toxin to decrease its toxicity, or enhancing immune system function.

The overall objective of this experiment was to determine the effect of these feed additives on the performance of nursery pigs fed diets contaminated with DON.

We used 5 nurseries for this experiment, 24 pens per nursery and 4 pigs per pen. Pigs were fed starter diets for 14 days before being offered the treatment diets (BW 9.02 ± 0.36 kg) for the next 14 days. All starter diets contained in-feed antibiotics.
Treatment diets were formulated to meet or exceed all requirements for pigs of this age. A positive control diet contained no contaminated corn, while the negative control diet was formulated with contaminated corn but no feed additives. Samples of corn which were pre-analyzed and shown to contain DON were used for 70% of the corn (35% in the final diet) in diets 2 to 12 to provide 2 ppm DON in the final diet. This concentration was chosen because a preliminary experiment indicated this amount would cause a measurable reduction in feed intake but would not be fatal.
Performance results are shown in Table 1. Pigs on the positive control tended to be heavier than those on the negative control by day 22 (0.50 kg, P = 0.09). Overall, pigs consuming diets contaminated with DON had reduced ADG and ADFI compared to those consuming the positive control diet free of DON (P < 0.001). Weekly measurements of body weight and feed intake showed that the decline in feed intake preceded the decline in growth (data not shown). Average daily gain and ADFI of pigs on the positive control was superior to those consuming the DON contaminated diet, regardless of the feed additive used. None of the feed additives ameliorated the effects of DON on feed intake or gain. Feed efficiency was unaffected by treatment (P > 0.05).
Based on a literature search and our preliminary experiment which indicated that 2 ppm would elicit a detectable decrease in feed intake but was non-fatal, we formulated the treatment diets to this level. Analyses of the diets indicated a mean concentration in the DON containing diets of 1.99 ppm, however, the individual diet concentrations ranged from 1.57 to 2.61 ppm.
The 1 tonne totes of contaminated corn were initially sampled from about 10 different locations within each tote to a depth of about 1 metre. These samples, composited by tote, were sent to two different labs for analyses for DON and moulds. The results were extremely variable, within and between the labs. Results from lab “A” ranged from 2.4 to 5.5 ppm with a mean of 4.5 while the results from lab “B” were 2.2 to 9.6 ppm and a mean of 6.9. We didn’t use the totes which displayed the most variability, however, the DON concentrations in our diets were still quite variable (Table 1).
The above illustrates the difficulty of working with mycotoxins. Obtaining representative samples for mycotoxin testing is very difficult, however it is imperative that a good sample is obtained or the results will be irrelevant. It has been estimated that almost 90% of the error associated with mycotoxin testing can be attributed to the method used to obtain the original sample. Because contamination within a field may be localized, a truck-load which has come directly from a field at harvest is likely to contain only discrete areas of contamination. Moreover, mycotoxin contaminated grains are heavier, thus within a truckload or during storage, some stratification may occur.
The “Grain Inspection, Packers and Stockyards Administration (GIPSA) of the USDA only recognizes samples which have been obtained using a probe. Moreover, at least 4 samples should be taken from each lot, preferably 7 to 9, depending on the size and thickness of the trailer. A 2000 to 2500 gram sample should be obtained. This sample should be ground and then subsampled to obtain the approximately 100 gram sample required by the lab. Producers are advised to contact the laboratory they will be using for the analyses to obtain specific sampling procedures and amounts required.
In summary, when nursery pigs were fed diets contaminated with approximately 2 ppm DON, feed intake declined by 10 % and growth by 7%. None of the feed additives mitigated this response, however, actual concentrations of DON in the test diets varied. This variability is an illustration of the difficulties inherent in correct sampling and analysis for mycotoxins.

The effects of sex and slaughter weight on growth performance and carcass traits of pigs intended for dry-cured ham from Teruel (Spain)

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This study investigates the effect of sex (barrows and gilts) and slaughter weight on growth performance and carcass characteristics using crossbred pigs from Duroc sires mated to Landrace x Large White dams. These pigs were intended for high quality dry-cured hams (Teruel ham) from Spain. It was concluded that barrows were better than gilts when intended for Teruel ham. Also, an increase in slaughter weight up to 130 kg in pigs impaired growth performance but improved some aspects of carcass quality that is required by the Teruel ham industry.

Antibiotic resistance genes and identification of staphylococci collected from the production chain of swine meat commodities

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The aim of this study was to evaluate the occurrence of staphylococci resistant to various antimicrobial agents in the entire production chain of swine meat commodities, from animal farming to final foods. Resistant staphylococcal isolates were collected and examined for the presence of 11 AR genes by means of specific PCRs; species identification and genetic correlation among the isolates were determined, as well. It was concluded that this investigation provided evidences of the wide occurrence of AR genes in resistant staphylococci derived from various steps of the production chain of swine meat commodities. It emerged that both coagulase-positive and -negative resistant staphylococci carry a number of AR genes demonstrating the spread of multidrug resistance in bacteria of food origin too, and the importance of resistance surveillance in the food production environment.

Implementation of Mandatory Country of Origin Labeling (MCOOL) in the Pork Industry

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The impetus for MCOOL came from northern plains beef producers as far back as the mid–1990s. The stated idea was that U.S. consumers deserve full information about the foods that they purchase and eat—an idea that is difficult to argue with. The underlying concerns, however, were growing imports of beef, pork, cattle and hogs from Canada and their perceived negative impact on U.S. markets. MCOOL is far less onerous for the pork industry than for the beef industry
for several reasons. First, Canada is the only source of imported pigs and market hogs. No hogs are presently
imported from Mexico due to animal disease restrictions. Second, all–in all–out production systems
keep pigs in defined, closed groups from early in life until slaughter in order to prevent the introduction of
disease. There is little or no comingling of animals as there is in the beef industry. This means that the origin
of an individual animal is the same as the origin of its group. Whether U.S. pig production increases
depends on the ultimate reaction of consumers, primarily to the multicountry labels. U.S. consumers
have a very positive view of things Canadian, though, so the negative impact may be small and will almost
certainly be smaller than consumers’ reactions to the presence of other countries such as Mexico, Brazil and
Uruguay on beef labels. If consumer reaction is not negative, Canada will continue to supply weaner and feeder pigs to U.S. feeders depending primarily on the exchange rate between the two countries’ currencies.

Entire male pigs in farrow-to-finish pens—Effects on animal welfare

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Castration performed without anaesthesia in piglets is a painful operation and it represents a potential animal welfare issue (Prunier et al., 2006). In an attempt to improve animal welfare, the Norwegian Parliament has passed a law banning the castration of piglets from 2009. Cessation of castration will relieve the animals from pain during and after surgery, but the rearing of entire males poses other welfare issues as entire male pigs are more aggressive and sexually active than castrates (Ellis et al., 1983; Giersing, 1998; Cronin et al., 2003). This could result in another animal welfare problem where high rank male pigs badger their pen mates of lower rank with biting, chasing and head knocks. Sexual behaviour (mounting of both gilts and boars) has also been reported as problematic, and can occasionally result in a high frequency of serious leg injuries to pen-mates (Rydhmer et al., 2004). It is important to recognise these problems and to find alternative rearing methods, which might ensure better animal welfare. Mixing of unacquainted pigs is usually followed by fighting (especially during the initial hours) until a new rank order is established in the group (Petherick and Blackshaw, 1987; Moore et al., 1994). The fighting behaviour tends to be more prolonged and serious when the weight differences between pigs are small (Rushen, 1987; Moore et al., 1994; Andersen et al., 2000; Schmolke et al., 2003). Mixing pigs is a very common practice in Norwegian pig production (and in many other countries also) both after weaning and when transferred to the fattening unit. The intention of the mixing is to reduce and balance the weight differences between pigs within the pens and to make the most out of available space. According to previous reports (Fredriksen et al., 2004), this practice can exacerbate sexual maturation of entire male pigs compared to when rearing them in sibling groups, in farrow-to-finish pens. Moreover, aggressive and sexual behaviour increases during puberty while mixing and moving animals. Furthermore reestablishment of the hierarchy among the pigs in the pen provokes aggressive and sexual behaviour. The hypothesis for the present study was that by keeping littermates together in stable groups, this process might be avoided and the onset of puberty delayed, thus resulting in a lower frequency of unwanted behaviour, lower skin lesion scores and consequently improved animal welfare. The frequencies of aggressive and sexual behaviour among finishing pigs were recorded in three different groups in one herd; farrow to finish-group (entires + gilts, siblings), mix-group (entires + gilts, mixed) and castrate-group (castrates + gilts, siblings). Frequencies of skin wounds were recorded in this herd and in an additional herd (only farrow to finish-group and mix-group) shortly before the animals were sent to slaughter. Higher skin lesion scores in the entire male pig groups were in accordance with the behaviour data. Rearing entire male pigs in sibling groups reduces aggressive behaviour, though the frequency of the aggressive behaviour bouts was still higher than it was in the castrate-group. The frequency of skin wounds in the farrow to finish-group was reduced to similar levels as in the castrate-group. The findings suggest that rearing entire males in sibling groups may be an appropriate management strategy for improving animal welfare in entire male pig production.

For more information the full article can be found at http://journals.elsevierhealth.com/periodicals/applan/issues

Social isolation elicits deficits in the ability of newly weaned female piglets to recognise conspecifics

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The goal of this study was to assess the ability of newly weaned female piglets to recognise familiar non-related
conspecifics and to examine how this was affected by weaning age and/or acute social isolation. It was found that neither weaning age nor social isolation affected the duration of social investigation in piglets exposed to unfamiliar conspecifics. However, when piglets weaned at day 11 were exposed to familiar conspecifics they investigated more than non-isolated pigs weaned on day 11, isolated piglets weaned on day 22 and non isolated pigs weaned at day 22. In conclusion, it may indicate that social recognition can be disrupted by 15 min of social isolation in piglets weaned on Day 11, but not in piglets weaned at Day 22.

For more information the full article can be found at http://journals.elsevierhealth.com/periodicals/applan/issues

Localization of heat shock proteins and histopathological changes in the kidneys of transported pigs

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To demonstrate the expression of heat shock proteins (Hsps) in the kidney, 5 kinds of Hsps, namely, Hsp70, Hsp72, Hsp86, Hsp90, and Hsp27, were examined in pigs after 6-h-transports by using western blot analysis. All 5 Hsps were detected in the kidneys of both the transported and control pigs. Hsp expression in the control pigs indicated that Hsps have some physiological functions in addition to stress-response functions. With the exception of Hsp27, a significant reduction was observed in all the levels of Hsps in the kidneys of the transport-stressed pigs after 6 h of transport, particularly in the levels of Hsp70 and Hsp72, which belong to the HSP70 family; and Hsp86 and Hsp90, which belong to the HSP90 family. The results indicate that 6-htransports are not only related to renal pathological injury but also to a reduction in most of Hsp levels in the kidney. However, slight Hsp27 induction (Pb0.05) indicates that Hsps that undergo different changes following transportation stress are involved in different physiological functions. Whether the decreased amount of a certain Hsp may indicate damage and/or overuse and whether Hsps actually protect kidney tissue from such overuse remain to be elucidated.

For more information the full article can be found at http://www.journals.elsevierhealth.com/periodicals/livsci

Potato (Solanum tuberosum L. cv. Gogu valley) protein as a novel antimicrobial agent in weanling pigs

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The objections of this study was to investigate the effect of feeding different levels of potato proteins on growth performance, nutrient digestibility, immune response, small intestinal morpholoy, and bacterial populations in feces and large intestine. These results suggest that potatoe protein may be an alternative to medicated feed with antibiotics because it showed antimicrobial activity by effectively reducing the population of coliform bacteria and also improved the performance of weanling pigs.

Effect of litter size and birth weight on growth, carcass and pork quality, and their relationship to postmortem proteolysis

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The objective of this study was to test if birth weight (BtW) influences growth, carcass characteristics, meat quality and postmortem (pm) proteolysis differently when pigs originate from small or large litters. The results confirm that the known effect of BtW on growth performance, wheras its effect on carcass characteristic and meat quality traits could only be partially demonstrated. Although litter size affected average BtW of the lightest-BtW and average size barrows, its effect on growth performance, carcass characteristics, and meat quality was minor. This study concludes that litter size affects swine growth and carcass and meat quality through its inverse relationship with birthweight.

Effects of sweeteners on individual feed intake characteristics and performance in group-housed weanling pigs

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To assess the effects of 2 high intensity
sodium saccharine-based sweeteners on individual
feed intake characteristics and performance of grouphoused
weaned pigs, one hundred ninety-eight 26-d-old
weanling pigs were given ad libitum access to 3 dietary
treatments containing: no additional sweetener (control),
150 mg of sweetener (Sucram C-150)/kg, or 150
mg of sweetener (Sucram 3D)/kg. At weaning, piglets
were allocated to 18 pens (11 pigs/pen) based on BW,
sex, and ancestry, and pens were randomly assigned to
3 treatments with 6 pens per treatment. The pens were
equipped with computerized feeding stations. During
the first 12 d, pigs were offered pelleted prestarter diets
that were replaced at once by pelleted starter diets
for the last 7 d of the 19-d experimental period. The
individual feed intake characteristics consisting of latency
time (interval between weaning and first feed
intake), initial feed intake (intake during the first 24
h following the first feed intake), the number of total
visits per day, and the number of visits in which feed
was consumed, together with the time and the feed
intake per visit, were determined for all piglets. Performance
traits and fecal consistency were determined
per pen for d 0 to 5, d 5 to 12, and d 12 to 19, as well
as for the total period (d 0 to 19). The initiation of feed
intake was not affected by the addition of high intensity
sweeteners to the diet. From 12 d postweaning, dietary
sweeteners caused the piglets to focus more on
feed intake and less on exploratory behavior, as shown
by the increased percentage of visits with feed intake
in pigs fed the Sucram 3D diet compared with those
fed the control diet (P = 0.002). The overall daily feed
intake increased with time but was not affected by the
addition of sweeteners. Nevertheless, dietary sweeteners
prevented the depression of feed intake on d 8 and
10 postweaning (d 8, P = 0.013; d 10, P = 0.014), which
seemed to coincide with an improved fecal consistency
score (d 5 to 12, P = 0.11; d 12 to 19, P < 0.001). However, the changes in feed intake characteristics and fecal consistency only resulted in numerical effects on postweaning pig performance (ADFI, P = 0.126; ADG, P = 0.140). The results of the present study indicate that weanling pigs need a certain period of time before clear effects of dietary sweeteners on individual feed intake characteristics and pig performance can be observed.