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Öğe Egg production dynamics and fecundity of Heterakis gallinarum residing in different caecal environments of chickens induced by fibre-rich diets(Elsevier, 2014) Das, Guerbuez; Abel, Hansjörg; Savaş, Türker; Sohnrey, Birgit; Gauly, MatthiasIn modern husbandry systems, feed rations for laying hens may contain high levels of dietary fibre, which may only be fermented intestinally. Depending on fermentation properties, the type of dietary fibre may influence the intra-caecal environment constituting the predilection site of Heterakis gallinarum. We investigated egg production dynamics and fecundity of H. gallinarum residing in different caecal environments induced through different types of dietary fibre. Growing layers were fed a standard (CON) or an insoluble(I-) or soluble- (S-) non-starch polysaccharides-(NSP) supplemented diet for the first 11 weeks (wk) of life in a twice-replicated experiment. At 3 wk of age, the birds were infected with 200 embryonated eggs of H. gallinarum. Starting from 3 wk post-infection (p.i.), individual daily total excreta were collected. The number of eggs per gram of faeces (EPG) was determined (N = 2240), and the number of eggs per day (EPD) were estimated. The birds were necropsied 8 wk p.i. and the worm burdens were quantified. The nematode began to lay eggs as early as 23 d.p.i. and thereafter laid on average 436 eggs/d. I-NSP- and S-SNP-supplemented diets expedited the onset of patency by approximately 5 days, and increased total egg excretion by 110% and 185%, respectively, due to higher worm counts. The latter diet (S-SNP) additionally increased total egg excretion by 94% due to enhanced fecundity. Longitudinally collected data showed that fecundity of the nematode (EPD/female) was relatively stable starting from the second week of the patent phase. Results suggest that NSP-induced enlargement of caeca favoured establishment of the nematode while effects of an intensified microbial fermentation through S-NSP were crucial for an enhancement in the worm fecundity. Based on the long-term data obtained from daily collections of total excreta in experimentally H. gallinarum-infected chickens, it is concluded that a diet enriched with pea bran as source of insoluble NSP increased worm egg production merely through elevated worm counts, whereas a diet supplemented with chicory root meal as source of soluble NSP elevated worm egg production through both increased worm counts, and more profoundly through enhanced fecundity. (C) 2014 Elsevier B.V. All rights reserved.Öğe Precision, repeatability and representative ability of faecal egg counts in Heterakis gallinarum infected chickens(Elsevier Science Bv, 2011) Das, Guerbuez; Savaş, Türker; Kaufmann, Falko; Idris, Ahmad; Abel, Hansjörg; Gauly, MatthiasThis study investigated whether a precise and repeatable quantification of Heterakis gallinarum egg excretion, which considerably reflects the actual worm burdens, can be achieved based on collection of the daily total amount of faeces from chickens. Three-week-old birds (N = 64) were infected with 200 embryonated eggs of H. gallinarum, and placed into individual cages 3 wk after infection for 5 wk to collect daily faeces (N = 2240). The total daily faeces was mixed and a randomly taken sample per bird was analyzed to estimate the numbers of eggs per gram of faeces (EPG) and total number of eggs excreted within 24h (EPD). A total of 235 daily faecal collections were randomly selected and further examined to determine between and within sample variations of EPG counts as a measure of precision. For this, two random faecal samples were taken from the daily produced faeces by a bird, and the EPG was determined for each of the samples (EPG1 and EPG2). The second faecal sample was analyzed once more to determine a parallel EPG2 count (EPG2a) of the suspended sample. Precision of an EPG count was defined as its relative closeness to the average of two EPG counts using a relative asymmetry index (Index(EPG)). At an age of 11 wk, i.e. 8 wk p.i. the birds were slaughtered and their worm burdens were determined. There were no significant differences between EPG1 and EPG2 (P = 0.764) nor between EPG2 and EPG2a (P = 0.700), suggesting that the differences between or within the samples were not different from zero. Correlations between EPG counts, as between and within sample coherences, were r = 0.85 and r = 0.86, respectively. Precision of EPG counts, as measured by Index(EPG), was not influenced by consistency (P = 0.870) and total amount of faeces (P = 0.088). However, concentration of eggs in faeces (mean EPG) had a significant effect on the precision of the EPG counts (P < 0.001). Similar results were also observed for the within sample precision (Index(EPG2)). A segmented regression analysis indicated an abrupt change in the precision of EPG counts as the response to changing egg concentration in the examined faecal samples. The precision of analyses remarkably heightened up to a breakpoint with an EPG count of <= 617. A similar breakpoint was also determined for within sample precision (EPG2 <= 621). Moderate repeatabilities (R = 0.49) for EPG and EPD were estimated in the first week of egg excretion, whereas the estimates were higher (R = 0.67-0.84) in the following weeks. Correlations between number of female worms with daily measured EPG and EPD increased to an almost constant level (r >= 0.70; P < 0.05) in a few days after the nematode excreted eggs and predominantly remained so for the rest of the sampling period. It is concluded that mixing daily total faeces provides samples with random homogenous distribution of H. gallinarum eggs. Precision of the EPG counts increases as the egg concentration in faecal sample increases. Egg excretion of H. gallinarum, quantified either as EPG or EPD, is highly repeatable and closely correlated with the actual worm burden of birds starting as early as in 5th wk of infection. (C) 2011 Elsevier B.V. All rights reserved.Öğe Precision, repeatability and representative ability of faecal egg counts in Heterakis gallinarum infected chickens (vol 183, pg 87, 2011)(Elsevier Science Bv, 2012) Das, Gurbuz; Savaş, Türker; Kaufmann, Falko; Idris, Ahmad; Abel, Hansjörg; Gauly, Matthias[Anstract Not Available]
