Selection for food conversion in broilers: Body composition of birds selected for increased body‐weight gain,food consumption and food conversion ratio

1. Body composition was determined in 9‐week‐old chickens sampled from four lines selected either for increased body‐weight gain (line W), for increased food consumption (line F), for decreased food conversion ratio (line E), or at random (line C), after three, four and five generations of selection.

2. After five generations of selection the proportions of carcass water (678 g/kg) and protein (187 g/kg) were highest in line E and lowest (636, 180 g/kg respectively) in line F. The proportion of fat was lowest (83 g/kg) in line E and highest (134 g/kg) in line F.

3. Lines W and C were similar and intermediate to lines E and F for all the carcass constituents.

4. There was more fat in females (115 vs 98 g/kg) and less protein (177 vs 190 g/kg) and water (652 vs 665 g/kg) than in males.

5. Line differences in carcass composition were not appreciably altered if birds were killed at equal weight rather than equal age.     

Selection for food conversion in broilers: Direct and correlated responses to selection for body‐weight gain,food consumption and food conversion ratio

1. Direct and correlated responses were determined after five generations in four lines of chickens selected either for increased body‐weight gain (line W), for increased food consumption (line F), for decreased food conversion ratio (line E), or at random (line C).

2. Realised heritability estimates calculated after five generations of selection were : 0–37 + 0.04 for weight gain (WG); 0.44 + 0.05 for food consumption (FC); 0.21 + 0.04 for food conversion ratio (FCR).

3. Realised genetic correlation estimates were: WG and FC, +0.71 ±006; WG and FCR, ‐0.40±0.09; FC and FCR, +0.27 + 0.09.

4. Zero‐generation heritability and genetic correlation estimates were greater than the realised estimates, and sex linkage appeared to be important in the expression of all three traits.

5. The genetic correlation between FC and FCR was asymmetrical with considerable positive response in FCR in line F (r_g = +0.79) but negligible response in FC in line E (r_g = —0.01).

6. There was an apparent plateau in response in FCR in line E from the third to the fifth selected generations.     

Are mycotoxins in food a health hazard?

The effects of mycotoxins are well known since antiquity. Modern trace analysis show the wide prevalence of mycotoxins in the food chain. Aflatoxins (AFB1, AFB2, AFG1, AFG2), trichothecenes (deoxynivalenol, T-2 Toxin, HT-2 Toxin), zearalenone, fumonisins (FB1, FB2) and ochratoxin A are the most important mycotoxins world wide. Foods of plant origin are normally contaminated more frequently and in higher concentrations than food of animal origin. The mean concentrations of mycotoxins analysed in European foods can be assed as low. This may be one reason why acute poisonings are rare incidences and why the limits of the tolerable daily intake (TDI) levels are exceeded only very seldom; however the population group "infant" exceed the preliminary TDI-level for trichothecenes. The consequences of a chronic intake of low amounts of mykotoxins is hardly to assess. A participation of the aflatoxins in the pathogenesis of primary liver cancer is considered as certain. Other coherence between the dietary intake of mycotoxins and specific clinical symptoms of man are not convincingly shown till now.     

Do we need pathogen-free livestock for food safety?

The reduction of the entry of pathogens in the food chain is an important premise in improving the safety of food of animal origin. Since food animals are the main reservoir for pathogens, the prevalence of pathogens in livestock is of great importance. Unfortunately, classical measures to improve animal health can not exclude the presence of the main food-borne zoonotic agents (Salmonella, Campylobacter, Listeria monocytogenes, verotoxinogene Escherichia coli, Toxoplasma gondii) in "clinically healthy" animals. Absence of pathogens in livestock must be regarded as an unrealistic aim. To achieve an effective improval of product safety through logistical, hygienic or technological measures both farmers and food producers need valid data about the prevalence of pathogens in livestock, in each animal and in raw material of animal origin, respectively. Yet available data are insufficient. New European directives and regulations concerning monitoring and control of zoonosis demand the systematic control of presence of zoonotic agents in livestock and later steps of the food chain.     

Additives in pet food: are they safe?

A good, nutritious diet is essential for the health and well-being of our domestic pets. Today, most pet dogs and cats are fed highly processed food bearing little resemblance to canine and feline ancestral diets. Additives are included in processed pet food to provide nutritional benefits, ensure food safety, and maintain the desirable features of colour, flavour, texture, stability and resistance to spoilage. This paper reviews the safety of various additives in processed pet food. Labelling, safety assessment, and ethical concerns regarding existing toxicity testing procedures are also considered. The adequacy of testing for many additives and the scientific basis for determining safety are questioned. Additives can be synthetic or ‘natural’ although the distinction can be blurred when naturally derived substances are synthesised in the laboratory, or extracted using a high level of physical and chemical processing. Although additives play important roles in processed food production, updated strategies and technologies may be required to establish their safety in the pet food industry.     

Responses in growth,food intake and food conversion efficiency to different dietary protein concentrations in meat‐type lines of Japanese quail

1. A total of 360 Japanese quail of 4 commercial meat‐type lines and two diet treatments (260 and 216 g/kg or 238 and 195 g/kg of crude protein (CP) in the starter and grower diet, respectively) were used.

2. The positive effect of a high CP diet on body weight was significant only for the first 4 weeks after hatching.

3. The mean age at inflection point of the growth curve (t ⁺) across lines and sexes was 1.4 d (0.6 to 2.8 d within line/sex groups) earlier for quail fed on a high CP diet than in quail receiving a low CP diet. The inflection (y ⁺) and asymptotic (A) weights were similar under both dietary protein concentrations. Nevertheless, the shape of the growth curve, characterised by the ratio y⁺1A and parameter of the maturing rate k, was significantly influenced by diet.

4. A higher food intake and less efficient food conversion were found for quail fed on a high CP diet in the period from 15 to 28 d of age.

5. The fattening traits such as body weight, cumulative food intake and food conversion, were not affected by dietary CP content at the age of 5 weeks.

6. The effects of line on body weight, food intake and food conversion are discussed.     

Where are the food animal veterinarian shortage areas anyway?

In 2010 the United States implemented the Veterinary Medicine Loan Repayment Program (VMLRP) to address perceived regional shortages in certain veterinary occupations, including food animal practice. With county as the unit of analysis, this paper describes a pair of models to evaluate factors associated with being designated a private practice shortage area in 2010. One model is used to explain food animal veterinarian location choices so as to provide an objective evaluation of comparative shortage. The other model seeks to explain the counties chosen as shortage areas. Model results are then used to evaluate the program. On the whole the program appears to perform quite well. For several states, however, VMLRP shortage designations are inconsistent with the food animal veterinarian location model. Comparative shortage is generally more severe in states that have no VMLRP designated private practice shortage counties than in states that do.     

Do dogs use a mirror to find hidden food?

Dog (Canis familiaris) cognition research that examines whether dogs are able to use a mirror as a problem-solving tool is rare. The aim of this study was to explore whether dogs could find food that was visible only via a mirror at the beginning of the experiment. In a laboratory setting, we exposed 44 dogs to a large mirror, attached at a 90° angle to an opaque barrier for 10 minutes. Dogs were allowed complete freedom of movement. For the first minute of the exposure phase, the owner and experimenter stood against a wall, ignoring the dog; afterward, both walked around the room for 9 minutes. The dogs could observe their movements in the mirror. Then, dogs were taught to associate a bowl with food, after which the bowl was surreptitiously placed behind the barrier, and the dogs were positioned so that they could see the reflection of the food in the mirror. Dogs were pseudorandomly assigned to the experimental group (n = 22) as described or a control group (n = 22), which was identical except that the mirror was covered during the testing phase. In the testing phase, dogs that could see the mirror were more likely to find the treat than dogs that could not (P = 0.032). Although fewer dogs in the control condition found the food, those that did were just as likely as those in the mirror condition to locate it within 3 minutes. This suggests that, although dogs' food-searching behavior can be triggered by the mirror's visual cues to locate food, some dogs used other cues that we were unable to control.     

Voluntary food restriction by laying hens mediated through dietary self‐selection

1. Individually caged Single Comb White Leghorn hens simultaneously received two diets which allowed selection of certain nutrients: these “ split‐diets “, essentially provided concentrated sources of either protein and energy (191 g crude protein, 12.82 MJ ME and 4.7 g Ca/kg diet), or calcium (107 g CP, 7.28 MJ ME and 131 g Ca/kg).

2. During four, 28‐d periods of lay, birds offered these split‐diets consumed some 7% less food in total than did control birds receiving a conventional diet ad libitum.

3. Calculation of nutrient intakes showed that birds on the split‐diets consumed significantly less protein, energy and calcium than the control birds.

4. Giving split‐diets also resulted in superior shell quality; treatment differences were also noted in the timing of oviposition.

5. It is suggested that the voluntary reduction in food intake noted for birds offered split‐diets is associated with an appetite for calcium.     

Disease outbreak in laying hens arising from the consumption of fumonisin‐contaminated food

1. During the last quarter of 1995 an unusual disease outbreak characterised by black sticky diarrhoea, severe reduction in food intake, egg production and body weight follow by lameness and death was observed in 2 layer farms in Andhra Pradesh. A total of 6700 hens of 64 weeks age and 3000 hens of 36 weeks age were affected.

2. Around 10% mortality and a 20% reduction in egg production was observed. Postmortem examinations showed pale yellow coloured livers with peripheral congestion, mild haemorrhage in the proventriculus and watery accumulations in the intestine.

3. The disease was traced to a new batch of food and its withdrawal improved the health status of the flocks.

4. Analysis of the diet indicated contamination with fumonisin B₁ up to 8–5 mg/kg and with aflatoxin B₁ up to 0.1 mg/kg.

5. Diarrhoea was induced in day old cockerels by feeding the suspect diet containing 8.5 mg/kg fumonisin Bi, and in laying hens by feeding a normal diet with fumonisin B₁ additions of 8 and 16 mg/kg.