A review of possibilities for control of Salmonella and other pathogenic bacteria in pig feed

Each category of pigs is susceptible to diseases caused by pathogenic bacteria, which negatively reflects on animal health, farm production results or meat quality. Animal feed is one of the potential reservoirs of pathogenic bacteria and infection source of domestic animals. Salmonella spp. is major microbiological hazard in animal feed. Thus, there is importance for implementation of strategies for preventing feed contamination with Salmonella, by minimizing dust, maximizing hygiene of space and processing equipment in feed mills and implementing control measures in each stage of feed production. Existing Salmonella feed contamination can be eliminated by conditioning and later different heat treatments (pelleting, extrusion, expansion) in production process while changing physical structure of the feed (coarsely or finely ground mash or pellets) can influence on conditions for Salmonella development in gastrointestinal tract of pigs. Contamination of feed by pathogenic bacteria and conditions for their development can be also controlled by addition of acidifiers, prebiotics, probiotics and, more recently, essential oils of plant origin, into feed. Various strategies for prevention of feed bacterial contamination, processes for feed decontamination, as well as possibilities for controlling pathogenic bacteria, especially Salmonella, in pig feed were presented and discussed in this article

The possibility of in vitro multi-enzymatic method application for the assessment of the influence of thermal treatments on organic matter digestibility of feed for ruminants

In vitro multi-enzymatic method is a two-step procedure that uses exogenous enzymes for incubation of feed that aim to imitate digestive processes in the animal. It is used for determination of organic matter digestibility (OMD) of various feedstuffs and complete mixtures used in ruminant nutrition. The aim of the present work was to determine whether this in vitro multi-enzymatic method can be applied for the assessment of the influence of thermal treatments on OMD of feed for ruminants. Samples of corn and complete mixture for cows (based on corn) were subjected to pelleting, steam flaking, micronization and extrusion. Statistical analysis of the results did not show significant increase of corn and complete mixture OMD after various thermal treatments compared to untreated samples, which can be explained by high digestibility of corn itself (exceeds 90%). Based on obtained results it can be concluded that applied in vitro method is not suitable for the assessment of the influence of thermal treatments on OMD of corn and corn based mixture, while future research should be broadened to analysis of samples with lower OMD, such as sorghum, oats and barley

Physical characteristics of feed collected from Italy and Serbia

The aim of this study was to investigate the physical quality of a selected lot of twenty animal feed samples collected in Italy and Serbia. Granulation of cattle and pig feed was finer in Italian than in Serbian samples. Flowability of samples from both countries in mash form were rated from fair to good (angle of repose >30°) while granulated samples (pellets and extrudates) had improved flowability (angle of repose 10 kg) than pelleted products (<8 kg). Durability of most of the extruded and pelleted products was higher than 95%. Generally, it was observed that most of the physical characteristics of the samples responded to recommendations, which showed that the similar practices are in use in both countries

Conductometric method for determining water stability and nutrient leaching of extruded fish feed

Water stability of eight samples of extruded salmon feeds was first determined by applying two gravimetric methods developed by the authors: gravimetric static and wet sieving method. Then, the conductometric method, primarily developed for investigation of nutrient leaching of feed into the water by the authors, was used for each sample. The aim of this study was to evaluate the potential of the conductometric measurement as a technique for determining water stability of extruded fish feed. In order to find any correlation between the results of two gravimetric tests and conductometric method, correlation analysis was employed. The results of static and wet sieving method were expressed as water stability index, which was expressed as the percent of remained dry matter of sample after being disintegrated in the water. The results of conductometric method were shown as conductivity curves for each sample, giving the insight in rate of nutrient leaching during the time. The obtained values of water conductivity showed no significant (p < 0.05) correlation with the results of static water method, while there was a negative significant (p < 0.05) correlation with the results of wet sieving method during first four hours of pellets soaking in water. The highest correlation coefficients were obtained within the first hour of conductivity measurement, demonstrating that proposed conductometric method had a potential to be applied as a rapid and simple method for determination and relative comparison of salmon feed water stability.[ Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III46012 and Grant no. TR31011

Reduction of cyanogenic glycosides by extrusion - influence of temperature and moisture content of the processed material

Тhe paper presents results of the investigation of the influence of extrusion temperature and moisture content of treated material on the reduction of cyanogenic glycosides (CGs) in linseed-based co-extrudate. CGs are the major limitation of the effective usage of linseed in animal nutrition. Hence, some technological process must be applied for detoxification of linseed before its application as a nutrient. Extrusion process has demonstrated several advantages in reducing the present CGs, since it combines the influences of heating, shearing, high pressure, mixing, etc. According to obtained results, the increase in both temperature and moisture content of the starting mixture decreased the content of CGs in the processed material. HCN content, as a measurement of GCs presence, ranged from 25.42 mg/kg, recorded at the moisture content of 11.5%, to 126 mg/kg, detected at the lowest moisture content of 7%. It seems that moisture content and temperature had the impact on HCN content of equal importance. However, the influence of extrusion parameters other than temperature and moisture content could not be neglected. Therefore, the impact of individual factors has to be tested together. [Projekat Ministarstva nauke Republike Srbije, br. III 46012

Changes in milk composition of domestic Balkan donkeys’ breed during lactation periods

Changes in the milk composition during early, middle and late stage of lactation period were monitored in 10 individual autochthonous donkeys of the Domestic Balkan breed. Animals were grazing ad libitum during early and middle lactation, while supplements (meadow hay, corn and corn stalks) were added during the late lactation period. The aim of this study was to evaluate the main compounds of donkeys’ milk during different periods of lactation. Based on the obtained results it was noticed that nutritional effects on milk composition were the greatest in the early and middle lactation. Chemical analysis indicated that donkeys’ milk was quite poor in dry matter (8.82-9.68%), fat (0.54-0.67%) and protein (1.44-1.79%), and conversely was high in lactose content (6.06-7.12%). Concentration of vitamin C varied significantly (P<0.05) during the lactation period and was very high (12.84-26.89 μg/mL) in comparison to milk from other animal species. Likewise, the content of lysozyme (1.95-3.29 g/L) and lactoferrin (1.56-3.14 g/L) during the early and middle lactation period showed an increase. Donkeys' milk did not show any significant differences in MUFA, n6-PUFA and UFA contents, while n3-PUFA, n6/n3 and UFA/SFA ratio showed a significant variability (P<0.05) during the lactation period.[Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III46012