Genetically modified feeds in animal nutrition 1st communication: Bacillus thuringiensis (Bt) corn in poultry,pig and ruminant nutrition

During the last few years, animal nutrition has been confronted with genetically modified organisms (GMO), and their significance will increase in the future.

The study presents investigations on the substantial equivalence of the transgenic Bt (Bacillus thuringiensis) corn and the corresponding nontransgenic hybrid Cesar and parameters of nutrition physiology such as digestibility and energy content for poultry, pigs and ruminants. The results of the analysed corn samples as well as of the silage samples illustrated substantial equivalence in all investigated ingredients, such as crude nutrients, amino acids, fatty acids, minerals and non‐starch polysaccharides. The results of the experiments using poultry, pigs, wethers and fattening bulls were not influenced by the genetic modification of corn. The determined values for the digestibilities and the energy contents for poultry, pigs and wethers were not affected by the used corn variety. Neither the examined parameters of the fattening experiments with bulls nor the slaughter results showed any significant differences between the bulls fed on silages made from the nontransgenic or transgenic corn.     

育肥饲料中植物油混合替代鱼油对中华绒螯蟹雄体脂肪酸代谢相关基因表达的影响

为研究植物油替代鱼油对中华绒螯蟹(以下简称河蟹)脂肪酸代谢产生的影响, 通过荧光定量PCR (qRTPCR)技术研究了河蟹脂肪酸碳链延长酶(Es-FAE)、9脂肪酸去饱和酶(Es-FAD9)、6脂肪酸去饱和酶b (Es-FAD6b)、脂肪酸结合蛋白3 (Es-FABP3)、脂肪酸结合蛋白9 (Es-FABP9)和脂肪酸结合蛋白10 (Es-FABP10)基因在不同组织中的表达情况, 以及育肥饲料中不同鱼油替代水平(鱼油替代水平分别为0、25%、50%、75%和100%, 记为饲料1#5#组)对河蟹雄体肝胰腺中这些基因mRNA表达水平的影响, 以探讨育肥中鱼油替代对河蟹雄体成蟹脂肪酸代谢的影响。结果表明: (1) Es-FAE、Es-FAD6b和Es-FAD9均在肝胰腺中表达水平最高, 在心脏和血淋巴中表达水平较低, 不同基因在其他组织中的表达规律有所不同; Es-FABP3、Es-FABP9和Es-FABP10主要在肝胰腺、肌肉、输精管和副性腺中表达水平较高, 在胃、肠和心脏中表达水平较低。(2) 随着饲料中鱼油替代水平的提高, 肝胰腺中Es-FAE-mRNA有显著增加趋势; 就Es-FAD6b而言, 饲料3#组显著高于饲料2#组, 其余各组间差异不显著; 随着饲料中鱼油水平的降低, 饲料1#3#组肝胰腺中Es-FAD9-mRNA也有显著增加趋势, 但差异不显著。(3) 就Es-FABP3而言, 饲料2#和3#组肝胰腺中表达水平最高,且显著高于饲料1#组(P0.05), 其余各组间差异不显著; 随着鱼油替代水平的升高, 肝胰腺中Es-FABP9和Es-FABP10-mRNA水平均有先上升后下降趋势, 但各组间差异不显著。综上, 河蟹脂肪酸代谢和转运相关基因在肝胰腺中表达水平最高, 饲料中不同鱼油替代水平对肝胰腺中上述基因mRNA表达水平具有较大影响。     

The autumnal fattening of the long-distance migratory garden warbler (Sylvia borin) is stimulated by intermittent fasting

To investigate the proximate influence of a changing food availability on the seasonal fattening of migratory birds, garden warblers (Sylvia borin) following postnuptial moult were food restricted once a week. Body mass, food intake, plasma hormone and metabolite levels were measured and compared to birds which always had ad libitum food access. The food-restricted birds increased their body mass significantly earlier than the controls. The accelerated fattening was initially not accompanied by hyperphagia and may be due to either an increased food utilisation efficiency or a reduced metabolic rate. An increase of basal glucagon and corticosterone and a decrease of insulin levels prior to fattening were not significant, however, they resulted in a significant decrease of the insulin:glucagon ratio. This ratio was also lower in food-restricted birds than in control birds and may account for the difference in the fattening progress. We conclude that seasonal fattening may be stimulated by a catabolic impulse which could be imposed in free-living birds by a decrease of food availability and/or by an increase of energy expenditure. A negative energy balance is hypothesised to be a common proximate factor affecting migratory as well as winter fattening. Accepted: 24 August 2000     

Prüfung einer quantitativen Futterrestriktion ab 3. Lebenswoche bei der Aufzucht von Junghennen der Mastrichtung im Käfig

The concentrations of Fe, Zn, Cu and Mn were determined in meat, inner organs, blood and residual carcass in a total of 24 barrows and gilts of 60 kg and 100 kg of live weight, respectively. The finisher diet contained 192 ppm Fe, 113 ppm Zn, 18 ppm Cu and 65 ppm Mn with, as calculated, a great proportion originating from the mineral supplement. During growth, the contents of Fe, Cu and Mn were significantly reduced. No sex differences occurred. In the lean meat of the 100 kg pigs, common values accounting for 1.1 mg Fe, 2.8 mg Zn and 0.05 mg Cu per 100 g were analyzed. The manganese concentration of 0.01 mg per 100 g, however, was considerably lower as the corresponding figure from nutrient tables. In the finishing period, the animals retained per animal and day about 18 mg Fe, 15 mg Zn and 0.2 mg Cu. Mn retention was not significantly different from zero. The low utilization rates calculated from these data can be partly explained by the moderately excessive supply in this fattening period. In order to reduce the trace element load of the soils, a considerably lower tolerance of excessive trace element contents in finisher diets has to be developed.     

Tasty straw pellets – Exploration of flavoured rooting material by pigs

Tail biting is a common problem in pigs kept in conventional fully slatted pens. Suitable enrichment materials can help to prevent the occurrence of this behavioural disorder by encouraging pigs to increase exploration behaviour. We investigated whether additional flavours can increase exploration behaviour in undocked pigs. Therefore, we offered straw pellets flavoured with either fried onion (FO), strawberry (SB), ginger, almond (AL), vanilla or without flavour (control) during rearing (eight groups in total) and fattening (16 groups in total). Flavoured pellets were offered in an altering order during intervals of 1 week in material dispensers. Exploration duration at the material dispensers was continuously recorded via an ultra-high-frequency radio-frequency identification system. Pigs were weighed weekly and their tail lengths and tail injuries were scored in four categories. For analysis, changes in tail length scores compared to the previous week were calculated as Δ-tail length. The different flavours affected pigs’ exploration durations in both rearing (factor flavour, P < 0.0001) and fattening (factor flavour, P < 0.0001). Highest exploration durations during rearing were recorded when straw pellets were flavoured with FO and AL compared to all others. During fattening, exploration duration was highest towards controls without significant difference to SB. Exploration durations additionally were affected by temporal effects, i.e. week and day during rearing (both factors: P < 0.0001) and fattening (both factors: P < 0.0001). During rearing, highest exploration durations were recorded in the first week and on the first day within week after changing the flavour of the straw pellets. During fattening, exploration durations varied between weeks and within weeks. The highest durations were recorded at the end of weeks, i.e. on the fifth and seventh days after material change. During rearing, tail injuries were affected by week (P < 0.0001). From the fourth week of rearing, the prevalence of tail injuries significantly increased. During the fattening period, tail injuries were affected by flavour (P < 0.05). Fattening pigs had fewest tail injuries after straw pellets flavoured with AL were offered. Altogether, based on the exploration durations, rearing pigs showed different preferences for the flavoured straw pellets but highly explored flavours differed between rearing and fattening pigs. Despite a weekly change of the flavour of straw pellets, exploration durations decreased during rearing but increased again in the transition between rearing and fattening. Thus, straw pellets with alternating flavours are a suitable possibility to provide environmental enrichment to pigs but will not prevent tail biting.     

Evaluating agro-industrial by-products as dietary roughage source on growth performance of fattening steers

Silages from pineapple peel, sweet corn husk and cob mixed with bagasse and vinasse were evaluated to determine their chemical composition and fermentation characteristics as well as feeding performance in fattening steers. The experiment, which lasted 90 days, involved 48 fattening steers (264 ± 37.4 kg BW) randomly allocated to three diets. Treatments included: a control diet containing rice straw and molasses (T1); diet containing bagasse–vinasse mixture including sweet corn husk and cob silage (BS; T2); and diet containing bagasse–vinasse mixture including pineapple peel silage (BP; T3). All treatments included a commercial concentrate feed (13% CP) and ad libitum rice straw throughout the experiment. Results from chemical analysis showed that dry matter (DM) of BS was higher than BP (P < 0.05), whereas the protein content of BS and BP was similar (P > 0.05). For fermentation characteristics, pH in BP was lower than BS (P < 0.05); in addition, acetic and butyric acids in BS were higher than BP (P < 0.05). Findings from growth trial showed that total DM intake in steers fed T1 was higher compared to the other dietary treatments (P < 0.05), whereas the average BW gain was found to be grater in T3 steers (P < 0.05). As result from our findings, bagasse–vinasse mixture with pineapple peel silage appeared to be a viable feed ingredient in fattening steer diet and moreover it could become an economically feasible agro-industrial by-product for farmers.     

Energetics of fattening and starvation in the long-distance migratory garden warbler,Sylvia borin,during the migratory phase

Garden warblers (Sylvia borin) were subjected to starvation trials during their autumnal migratory phase in order to simulate a period of non-stop migration. Before, during and after this treatment the energy expenditure, activity, food intake and body mass of the subjects were monitored. Assimilation efficiency was constant throughout the experiments. The catabolized (during starvation) and deposited body tissue (during recovery) consisted of 73% fat. Basal metabolic rate was decreased during the starvation period and tended to a gradual increase during the recovery period. The reduced basal metabolic rate can possibly be attributed to a reduced size/function of the digestive system, which is consistent with the sub-maximal food intake immediately after resuming the supply of food to the experimental birds. The observed reductions in basal metabolic rate during starvation and activity during recovery can be viewed as adaptations contributing to a higher economization of energy supplies. The experimental birds were unable to eat large quantities of food directly after a period of starvation leading to a comparatively low, or no increase in body mass. Such a slow mass increase is in agreement with observations of migratory birds on arrival at stop-over sites.Abbreviations BM body mass - BMR basal metabolic rate - LBM lean body mass - RQ respiratory quotient     

Influences of the feeding ecology on body mass and possible implications for reproduction in the edible dormouse (<Emphasis Type="Italic">Glis glis</Emphasis>)

The edible dormouse (Glis glis) is a small rodent and an obligate hibernator. Dormice undergo strong fluctuations of reproductive output during years that seem to be timed to coincide with future food supply. This behaviour enables them to avoid producing young that will starve with a high probability due to food shortage, and to increase their lifetime reproductive success. Aims of this study were to elucidate the extent to which feeding ecology in the edible dormouse has an impact on body mass and the fatty acid (FA) pattern of the white adipose tissue (WAT) before and after hibernation, which in turn might influence reproductive status in spring. Dormice show strong seasonal fluctuations of the body mass, which is reduced by one third during hibernation. Body mass and its changes depend on autumnal food availability as well as on the dietary FA pattern. During the pre-hibernation fattening period, dormice eat lipid rich food with a high content of linoleic acid. During hibernation, linoleic acid content is slightly but significantly reduced and body mass loss during winter is negatively correlated with the pre-hibernation linoleic acid content in the WAT. No relation between reproductive status and body mass, body condition or the FAs pattern of the WAT could be detected. However, in a year of high reproduction, dormice commence the shift to seed eating earlier than in a year of low reproduction. These seeds could be either a predictor for future food supply in autumn, or represent a high-energy food compensating high energetic costs of sexual activity in male edible dormice.     

Content and deposition of major mineral elements in different tissues and empty body of growing bulls of the german simmental breed

54 bulls of the German Simmental breed were fed either on a high energy level (maize silage ad libitum and 1.8 kg concentrate) or on a low energy level (maize silage restrictively and 1.0 kg concentrate). In dependence on feeding intensity a mean daily weight gain of 870 or 1210 g was obtained. Animals were slaughtered with a live mass of 200 kg, 350 kg, 500 kg, 575 kg and 650 kg. Empty body was divided into 13 cuts and afterwards separated into lean, bone and adipose tissues and tendons. Major mineral element content was determined in these tissues as well as in the noncarcass parts.

In the lean tissue the mean content (200 kg) of 0.3 g calcium, 10 g phosphorus, 1 g magnesium, 2.3 g sodium and 14.8 g potassium/kg dry matter decreased slightly with rising live mass (200–650 kg). The contents of major mineral elements were much higher in bone tissue. For the fattening period from 200 to 650 kg of live mass mean contents of 151.5 g calcium, 71.3 g phosphorus, 3.2 g magnesium, 5.1 g sodium and 1.1 g potassium per kg DM were analysed. Mineral element content of bone tissue increased with rising live mass as well as animals on low feeding intensity showed a higher mineral content than on high energy level. In all, major mineral element content in fat tissue was very low. In noncarcass parts head and legs calcium and phosphorus had analogous to bone tissue the highest concentration. Hide showed a high content of sodium, whereas organs and digestive tract had a high content of potassium and phosphorus. Total mass of major mineral elements in the different tissues increased above all in the fattening period of 200 to 350 kg. In carcass as well as in empty body, mass of calcium and phosphorus was much higher than magnesium, sodium and potassium. Also animals on low feeding intensity showed a higher mass of major mineral elements in carcass and empty body than animals on high energy feeding intensity. The intensively fed bulls had a mean deposition of 12.7 g calcium, 6.9 g phosphorus, 0.37 g magnesium, 1.2 g sodium and 2.1 potassium per 1000 g of empty body weight gain, whereas restrictively fed bulls deposited in average 15.0 g calcium, 7.8 g phosphorus, 0.4 g magnesium, 1.2 g sodium and 2.4 g potassium per 1000 g of empty body weight gain.