Native Chicks Research Articles

Climate-Adapted Circular Poultry Production: Salt-Treated Wild Yam Tubers as Sustainable Supplementary Feed Ingredients Via Osmosis-Based Detoxification

Wild yams have tremendous potential as nutritious food and feed sources. However, anti-nutritional factors like oxalates and phenolics limit their utilization. This study evaluated salt-assisted osmosis for detoxification and nutritional improvement of wild yam tubers and assessed their application as a feed ingredient for native chickens. Wild yam tubers were treated with 10%, 20%, and 30% salt solutions to induce osmosis-based leaching of water-soluble toxins. Proximate analyses confirmed nutrient retention post-treatment. Four isonitrogenous experimental chicken feeds were formulated with varying proportions of standard commercial diet and salt-treated wild yam meal. Ninety-six 5-week-old native chicks were randomly allocated to the diets for 8 weeks to assess growth performance, intake, meat quality, and physiological parameters. Toxin levels decreased up to 50% with a 30% salt solution while beneficial nutrients were preserved. The inclusion of treated yam meal did not adversely affect growth rate, though higher salt levels reduced feed palatability. Carcass traits remained unaffected although minor organ weight and serum biomarker changes indicated physiological stress. Salt-assisted osmosis the demonstrates potential for efficient detoxification to promote better utilization of under-explored nutritious crops like wild yam as sustainable, alternative feed sources without compromising nutritional adequacy. Further optimization to prevent anti-nutrient reaccumulation and physiological imbalance is recommended before scalability for food/feed security.

Effect of fiber source diet supplement on growth performance, carcass quality, oxidative stress and intestinal morphology in Thai native chicken (Pradu Hang dum)

Dietary fiber was used for reduce feed cost in local animal production. However, other advantages effects were interesting to study. Therefore, the objective of this research was to investigated effect of fiber source diet on performance, carcass quality, oxidative stress and intestinal morphology in Thai native chicken. A total of 300 one-day-old (mixed sex) crossbred native chicks (Pradu Hang dum) were randomly assigned to 5 treatments in completely randomized design (CRD). Each treatment had 10 replicates with the crossbred native chickens 6 bird/replicates (1 to 12 weeks of age) were given different levels of banana stem and Napier grass. Treatment diets received as follows a basal diet; 100%, no supplement or control group (CON), basal diet; 95%, 90% supplemented with the banana stem at 50 g/kg, 100 g/kg (BS 5%, BS 10%) of diet, respectively, and basal diet; 95%, 90% supplemented with the Napier grass at 50 g/kg, 100 g/kg (NG 5%, NG 10%) of diet, respectively. The results of the study showed that the use of fiber source: banana stem at 50 g/kg and Napier grass 100 g/kg of the diet improved growth performance. The result showed benefits to increase body weight, improve feed conversion ratio (FCR) and feed cost per gain (FCG), improve to gut health by increase villus height (VH), Villus width (VW) in duodenal and jejunal small intestine morphology, reduced malondialdehyde (MDA) levels in serum (p < 0.001). In addition, significantly higher thigh meat percentage (p < 0.05) without effecting visceral weight and overall carcass percentage.

Sex Detection of Chicks Based on Audio Technology and Deep Learning Methods.

The sex detection of chicks is an important work in poultry breeding. Separating chicks of different sexes early can effectively improve production efficiency and commercial benefits. In this paper, based on the difference in calls among one-day-old chicks of different sexes, a sex detection method based on chick calls is designed. Deep learning methods were used to classify the calls of chicks and detect their sex. This experiment studies three different varieties of chicks. The short-time zero-crossing rate was used to automatically detect the endpoints of chick calls in audio. Three kinds of audio features were compared: Spectrogram, Cepstrogram and MFCC+Logfbank. The features were used as the input in neural networks, and there were five kinds of neural networks: CNN, GRU, CRNN, TwoStream and ResNet-50. After the cross-comparison experiment of different varieties of chicks, audio features and neural networks, the ResNet-50 neural network trained with the MFCC+Logfbank audio features of three yellow chick calls had the highest test accuracy of 83% when testing Three-yellow chicks' calls. The GRU neural network trained with the Spectrogram audio features of native chick calls had the highest test accuracy of 76.8% when testing Native chicks' calls. The ResNet-50 neural network trained with Spectrogram audio features of flaxen-yellow chick calls had the highest test accuracy of 66.56%when testing flaxen-yellow chick calls. Multiple calls of each chick were detected, and the majority voting method was used to detect the sex of the chicks. The ResNet-50 neural network trained with the Spectrogram of three yellow chick calls had the highest sex detection accuracy of 95% when detecting the three yellow chicks' sex. The GRU neural network trained with the Spectrogram and cepstrogram of native chick calls and the CRNN network trained with the Spectrogram of native chick calls had the highest sex detection accuracy of 90% when detecting the native chicks' sex. The Twostream neural network trained with MFCC+Logfbank of flaxen-yellow chick calls and the ResNet-50 network trained with the Spectrogram of flaxen-yellow chick calls had the highest sex detection accuracy of 80% when detecting the flaxen-yellow chicks' sex. The results of the cross-comparison experiment show that there is a large diversity between the sex differences in chick calls of different breeds. The method is more applicable to chick sex detection in three yellow chicks and less so in native chicks and flaxen-yellow chicks. Additionally, when detecting the sex of chicks of a similar breed to the training chicks, the method obtained better results, while detecting the sex of chicks of other breeds, the detection accuracy was significantly reduced. This paper provides further perspectives on the sex detection method of chicks based on their calls and help and guidance for future research.

​Effect of Hydrilla verticillata in Feed on Production Performance and Carcass Characteristics of Thai Native Chickens

Background: Producing Thai native chickens through feed commercial is costly. To reduce the cost, native chicken could be fed with local plants or agricultural waste. Hyrrilla verticillate, a dominate macrophyte in Songkhla Lagoon, contain high crude protein and nitrogen free extract. Therefore, this research studied the use of Hydrilla verticillate in Thai native chicken diet on production performance, carcass characteristics and production cost. Methods: The experiment was executed in a completely randomized design (CRD) with 180 one-day-old commercial Thai native chicks. Four dietary treatments supplemented with 0%, 5%, 10% and 15% Hydrilla verticillata were formulated for three different phases of the experimental chickens: starter (1-4 weeks), grower (5-8 weeks) and finisher (9-12 weeks). Two chickens from each replicate were chosen for the carcass characteristics study. Result: During the starter phase, there was no notable effect shown among the chickens fed with the diet containing Hydrilla verticillata in terms of feed intake (FI) and body weight gain (BWG) (P greater than 0.05). The control chickens had best feed conversion ratio (FCR) (P less than 0.05), while the grower and the finisher periods, provided with different levels of Hydrilla verticillata, revealed no apparent differences (P greater than 0.05) concerning FI, BWG and FCR. Considering carcass characteristics, there were significant differences in live weight (LW) (P less than 0.05). But, no significant differences between treatments for hot carcass percentage, pectoralis majors, pectoralis minorstrip, thighs, wings, drumsticks and total edible carcass (P greater than 0.05). There were also statistical divergences regarding gizzard weight (GW) (P less than 0.05).

THE INFLUENCE OF HOLISTIC FEED ON PERFORMANCE OF SUPER NATIVE CHICK

This study determines effects of raw material feed (derived from corn, bran, soybean pods, concentrates and Indigofera zollingeriana local to Magelang) on the performance of native chicks. Performance was measured by feed consumption, body weight gain, Feed Conversion Ratio (FCR), mortality, and morbidity. This experiment used Completely Randomized Design (CRD) with three different feed treatments, and each treatment consisted of 30 free-range female chicks as replicants, from 0-4 weeks old. Super native chick feed was formulated by trial and error by mixing all ingredients: corn, bran, soybean pods, Indigofera zollingeriana, and premix. After mixing, a proximate test determined the nutritional content of the feed. Feed was then administered to chicks. Quantity of feed was administered according to age. The results obtained in the study were analyzed descriptively and statistically using the Variance Test (ANOVA) for the variables of body weight gain, feed consumption, and FCR. The Kruskal Wallis test was used via SPSS 26 program for mortality and morbidity variables with three treatments (T1, T2, and T3) and three replications. Each treatment consisted of 30 research individuals. Results showed that the super native chicks on varied protein diets had a significant difference in performance (P0.05), with feed 3 performing the best feed 3 produced a feed consumption of 430.20 g/chick and body weight gain of 174.67 g/chick, along with 2.46 FCR, 0% mortality, and 3.33% morbidity. The conclusion this study is holistic feed made from local ingredients with the addition of Indigofera zolliengeriana had a significant effect on increasing average daily gain, increasing feed consumption, and reducing feed conversion ratio (FCR) in native super chick.

Effect of Incorporating Early Feather Restriction Gene (KS) From Native Chicken to Purebred Chicken

Fast growing chicken suffers more in a hot humid condition than a slow growing one. The slow feathering affects the insulation mechanism of the chicken, thus enhance birds ability to dissipate heat during heat stress to a greater extent. As a consequence, slow feathered birds are more adaptive to hot humid environmental conditions. This study was undertaken to investigate the effect of incorporating early feather restriction gene (KS) in exotic population. A total of 34 slow feathered (SF) native chicks with KS gene of 28-day-old were collected from different villages and markets and were reared up to sexual maturity. After attaining sexual maturity, 2 males and 8 females of SF native chicken were randomly chosen to make a di-allelic cross with rapid feathered (RF) Rhode Island Red (RIR) and Fayoumi (FY). The crossbred progeny of each cross were reared up to 105 days to assess growth, survivability, heat tolerance and carcass yield under hot humid Bangladeshi condition. The collected data were arranged in a 3(genotype)×2(feather pattern)×9(age) factorial experiment in a Completely Randomized Design (CRD) and analyzed by SAS. Among genotypes, the highest survivability was obtained in Desi×Fayoumi (96.7%) and in SF chicks (96.1%) and the lowest in Desi×RIR (91.5%) and in RF chicks (90.5%). The SF chicks exhibited an average 8% heavier live weight than that of their RF counterparts. The cloacal temperature varied among genotypes and between feathering patterns (FP); being highest in Desi×RIR (430C) and in RF chicks (41.60C) and lowest in RIR×Desi (400C) and in SF chicks (41.40C). In case of Desi×RIR, RIR×Desi and Desi×Fayoumi, cloacal temperature increased linearly by 0.047, 0.044 and 0.0320C for each gram of live weight increase. Further, the cloacal temperature increased linearly by 0.036 and 0.0440C for the increase of each gram of live weight gain in case of RF and SF chicks, respectively. There was no significant (P>0.05) difference of dressing percentage for the effect of either genotype or FP (55.4% for SF vs. 46.6% for RF birds). Genotype and FP had significant effects (P<0.05; P<0.01) on total meat yield; being highest in Desi×RIR (24.6%) and in SF birds (26.2%) and lowest in Desi×Fayoumi (21.4%) and in RF birds (20.6%). Breast meat yield of SF birds (9.2%) was significantly (P<0.01) higher than that of RF birds (7.1%). The highest thigh meat yield was obtained in Desi×RIR (7.6%) and in SF birds (8.3%) and the lowest in Desi×Fayoumi (6.7%) and in RF counterparts (6.0%). The highest drumstick meat yield was obtained in RIR×Desi (5.6%) and in SF birds (5.9%) and the lowest in Desi×Fayoumi (5.0%) and in RF birds (4.8%). Genotype and FP had significant interaction effect on total meat yield as well as fractional meat yields. The study revealed that incorporation of ‘Ks’ gene in the exotic one by crossing with native chicken and rearing under hot humid environment may be a means of improving growth, survivability, heat tolerance and carcass yield.

Pathological and virological analysis of concurrent disease of chicken anemia virus infection and infectious bronchitis in Japanese native chicks.

A concurrent infection of chicken anemia virus (CAV) and infectious bronchitis virus (IBV) was detected in Japanese native chicks in 2017, in which a high mortality rate (97.7%) was recorded in a small flock of 130 chicks exhibiting poor growth. Histological examination revealed that the affected chicks exhibited two different pathological entities: one was severe hematopoietic and lymphocytic depletion with abnormally large cells containing intranuclear inclusion bodies of CAV, whereas the other was renal tubular necrosis due to IBV infection. Immunohistochemistry detected CAV antigens in the bone marrow, liver, and spleen as well as IBV antigens in the kidneys, trachea, and air sacs. CAV was isolated from the liver sample of the chicks, and the isolated strain was designated as CAV/Japan/HS1/17. A phylogenetic analysis of the CAV VP1 gene revealed that CAV/Japan/HS1/17 is genetically similar to Chinese strains collected from 2014 to 2016. An experimental infection was performed using CAV/Japan/HS1/17 and specific-pathogen-free chicks to determine the pathogenicity of CAV/Japan/HS1/17. The isolate caused 100% anemia and 70% mortality to chicks inoculated at one day old, 80% of chicks inoculated at seven days old also developed anemia, and 10% died from CAV infection. These results suggest that the unusually high mortality in Japanese native chicks can be attributed to dual infection with both CAV and IBV. The results of the experimental infection suggest that CAV/Japan/HS1/17 has a pathogenic potential to specific-pathogen-free chicks and a relatively higher pathogenicity than previous Japanese CAV strains.

한국 재래닭에서 아연 보충급여가 항산화 지표 및 아연 운반 유전자 발현에 미치는 영향

한국 재래닭에서 아연 보충급여가 항산화 지표 및 아연 운반 유전자 발현에 미치는 영향

아연 보충급여에 따른 한국재래계의 성장, 사료이용성, 장기무게, 혈액생화학적 성상, 장기무게 및 소화효소 활성도에 미치는 영향

The aim of the study was to investigate the effects of dietary supplementation of zinc (Zn) sources (zinc oxide and Zn-methionine) on performance, organ weights, blood biochemical profiles, and digestive enzymes of the pancreas and small intestine in Korean native chicks (KNC). A total of 144 KNC (n=6) were fed a basal diet (CON, 100 ppm of Zn), a basal diet supplemented with 50 ppm of Zn with ZnO (ZNO), or a basal diet supplemented with 50 ppm of Zn with Zn-methionine (ZMT) for 28 days. There was no significant difference in body weight, gain, feed intake, and feed conversion ratio among the three groups. The relative weights of the liver, spleen, and intestinal mucosa were unaffected by the dietary source of Zn, whereas pancreas weight in the ZNO group decreased (<italic>P</italic>&lt;0.05) compared with that in the CON and ZMT groups. Blood biochemical components including aspartate aminotransferase, and alanine aminotransferase were unaffected by dietary Zn supplementation. Pancreatic trypsin activity in the ZNO and ZMT groups was significantly (P&lt;0.05) enhanced compared with that in the CON group. However, the activities of α-amylase and carboxypeptidase A were not altered by dietary Zn supplementation. The activities of maltase and sucrase were unchanged, whereas the activity of leucine aminopeptidase tended (<italic>P</italic>=0.08) to be increased by dietary Zn supplementation. In conclusion, the supplementation with 50 ppm of ZnO or Zn-methionine resulted in an activation of protein digestive enzymes in the pancreas and small intestine without affecting animal performance in KNC.

A novel approach for determination of chicken sexing at an early stage of development by using loop-mediated isothermal amplification method

The monomorphism of newly hatched chicks is a major hurdle for poultry farmers at the time of sexing. The traditional sexing techniques are inaccurate and time-consuming. Therefore, the present study aimed to develop a loop-mediated isothermal amplification (LAMP)-based sex determination method to obtain a higher separation accuracy rate as compared to conventional methods. LAMP is a simple, quick, and relatively inexpensive diagnostic tool. Genomic DNA was extracted from the blood samples of Leghorn and Korean native chicks for LAMP. Two sets of primer were designed, consisting of four isothermal amplification primers in each, to amplify the female sex-specific sequence (HUR0417) of the PKCIW gene. We found that the corresponding female samples showed significant amplification of the PKCIW gene, while this was not observed in the male samples. Moreover, this method produced results in less than 1 h. The present investigation suggests that the LAMP-based sexing method is a sensitive, accurate, and time-saving method in chicks at an early age compared to the conventional sexing methods.

Bacteriological studies on native and imported apparently healthy one day old chicks

One thousands and eighty one day old chicks were examined for isolation of different bacteria. Salmonella was detected in 11.7% in native chicks while 5.2% among imported chicks, E. coli was isolated from 17.6% in native chicks while 23.6% in imported, Staph aureus was present in 29.4% in native and 5.2% in imported chicks. Serological typing of Salmonella was Salmonella Norwich, Salmonella Wilhelburg in native chicks while in imported chicks were Salmonella Brancoster, Salmonella Sekondi II. E .coli sero-typing reveled O125, O153, O86a in native chicks while in imported chicks were O26, O78, O36, O15, O124, O169, O6, O28 and one un-typeable strain. Seven Staph aureus isolates five from native and two from imported. Antibiogram of isolated bacteria was done. All Salmonella strains were sensitive to Gentamycin while all E. coli strains were sensitive to Amoxicillin + Clavulanic acid and Nitrofurantoin. All Staph aureus isolates were sensitive to Amoxicillin + Clavulanic acid.

사료 단백질 및 에너지 수준이 재래닭의 성장과 혈액의 성상에 미치는 영향

본 연구는 재래닭의 사료 급여 체계 확립에 필요한 기초 자료를 제공하고자 두 차례의 사양시험을 수행하였다. 공시 동물은 시험 1(<TEX>$0{\sim}5$</TEX>주)에서 재래닭(우리맛닭) 1일령 수컷 720수를 사용하여 펜당 20수씩 배치하였고, 시험 2(<TEX>$6{\sim}10$</TEX>주)에서는 동일한 종의 재래닭 35일령 480수를 펜당 20수씩 공시하였다. 사료내 에너지 수준과 CP 함량은 시험 1에서 3,000, 3,050, 3,100 kcal/kg, 21, 22, 23%이며, 시험 2에서는 3,050, 3,100, 3,150 kcal/kg, 18, 19%로 급여하였다. 조사 항목은 증체량, 사료 섭취량을 측정하여 생산성을 계산하였으며, 각 실험 종료시 혈액을 채취하여 분석하였다. 시험 1 : <TEX>$0{\sim}5$</TEX>주간 에너지 수준에 따른 생산 능력은 증체량에서 3,050, 3,100 kcal/kg 처리구가 3,000 kcal/kg 처리구보다 통계적으로 개선되었으며(P<0.05), CP 함량에 의한 유의성은 나타나지 않았다. 에너지 수준에 따른 사료 섭취량은 증체량과 상이한 경향을 나타내어 3,000 kcal/kg 처리구가 3,050, 3,100 kcal/kg 처리구보다 높았으며(P<0.05), CP 함량에 의한 차이는 21% 처리구가 22, 23% 처리구보다 높게 나타내었다(P<0.05). 사료 효율은 증체량과 동일한 경향으로 3,050, 3,100 kcal/kg 처리구가 3,000 kcal/kg 처리구보다 통계적으로 개선되었으며(P<0.05), CP가 높은 수준의 사료를 급여시에 낮은 수준의 CP 처리구에 비하여 개선되었다(P<0.05). 혈중 총단백질과 글루코스, 총콜레스테롤은 에너지 수준과 CP 함량이 높아질수록 증가하는 경향을 보였으며, HDL은 에너지 수준이 높아질수록 증가하는 경향을 보였고, LDL은 CP 함량이 낮은 처리구에서 증가하였다. 시험 2 : <TEX>$6{\sim}10$</TEX>주간 사료내 에너지 수준에 따른 증체량의 변화는 3,100 kcal/kg 처리구보다 3,050, 3,150 kcal/kg 처리구가 개선되었으며, CP 함량 18%처리구가 19%처리구보다 통계적으로 높았다(P<0.05). 또한, 에너지 수준에 따른 사료 섭취량은 증체량과 같은 경향을 보였으며, CP 함량 19%처리구가 18%처리구보다 개선되었다(P<0.05). 사료 효율에서 사료의 CP 함량에 의한 통계적인 차이는 없었으며, 에너지 수준이 높아질수록 개선되는 경향을 나타내었다. 혈액내 총단백질과 글루코스는 CP 함량이 높을수록 증가하는 경향을 나타내었으며 중성지방은 사료의 에너지 수준이 높아질수록, CP 함량이 낮아질수록 증가하였다. HDL은 에너지 수준이 높아질수록 유의적으로 증가하였으며(P<0.05) LDL은 중성지방과 같은 결과를 나타내었다. 본 연구 결과, 재래닭의 생산 능력 극대화를 위한 적정 사료의 ME와 CP 함량은 사육 전기 5주간에는 3,050 kcal/kg, 22%, 사육 후기 5주간에는 3,150 kcal/kg, 19% 수준이 적합할 것으로 사료된다. Two experiments were conducted to establish the basic data of feeding system in cross-bred Korean native chicks. A total of seven hundred twenty chicks were replaced the 36 floor pen for the first five weeks with <TEX>$3{\times}3$</TEX> factorial design in Experiment 1. Four hundred eighty of five weeks old chicks were raised from six to ten weeks of age with <TEX>$3{\times}2$</TEX> factorial design in Experiment 2. Dietary ME and CP were formulated to contain 3,000, 3,050, 3,100 kcal/kg and 21, 22, 23%, respectively in Experiment 1 and 3,050, 3,100, 3,150 kcal/kg and 18, 19% in Experiment 2. Weight gain, feed intake were measured and calculated the feed conversion. Blood were collected and analyzed at the end of experiments. In Experiment 1, weight gain showed significantly higher in 3,050, 3,100 kcal/kg treatments than 3,000 kcal/kg treatment (P<0.05), but was not different in CP treatments. Feed intake was statistically high in 3,000 kcal/kg treatment compared with 3,050 and 3,100 kcal/kg ones (P<0.05), and more increased in 21% CP treatments compared to that of 22 and 23 CP treatment (P<0.05). Feed conversion of birds fed 3,050 and 3,100 kcal/kg diet showed much lower than 3,000 kcal/kg treatments (P<0.05). FCR was signicantly improved (P<0.05) in chicks fed diets containing 21 and 22% CP as compared to that fed 20% CP. Blood protein, glucose, and total cholesterol tended to increase in high energy and diet treatments. Blood HDL was increased as dietary energy increased, whereas LDL increased in low CP treatments. In Experiment 2, weight gain was not consistent between treatments, but more increased in 18% CP treatments compared to that of 19% CP treatment from six to ten weeks old in cross bred chicks (P<0.05). Feed intake was similar to the result of weight gain, but more increased in 19% CP treatment than 18% CP treatment (P<0.05). There were no statistically difference in FCR, but seemed to improve as dietary ME increased. Blood total protein and glucose increased as dietary CP was high, but triglyceride and HDL increased in high versus low ME (P<0.05). The results of these experiments suggested that optimum dietary ME and CP, were 3,050, 3,150kcal/kg and 22, 19% for the first five weeks and second one, respectively.

Peningkatan Nilai Nutrisi Cangkang Siput Sebagai Sumber Mineral Pada Ransum Ayam Buras Periode Grower

The objectives of the present investigation were to evaluate the effect of using shell of fresh water snails in 3 different processing forms (raw coarse ground, raw and roasted finely ground) as the major source of calcium in the diets on the performance of growing native chickens (12-24 weeks of age). Four dietary treatments were a control diet containing 2 % of oyster shell meal and three others consisted of 2 % of freshwater snail shell in the form raw coarse ground, raw and roasted fine ground. The diets were offered to forty growing native chicks, which were randomly divided into four groups, each amounting of 10 chickens as replication. Parameters measured included: body weight gain, feed intake, FCR, carcass weight and net return. The results showed that roasting of shell of freshwater snail prior to incorporate in the rations could significantly improve the body weigh gain, feed intake and FCR However, the net return was negative mainly due to high feed cost. Chickens fed on diet containing raw coarse grounded shell was found the highest net return.

Effects of L-carnitine administration on growth performance, carcass traits, blood serum parameters and abdominal fatty acid composition of ducks

Effects of L-carnitine administration via drinking water on growth performance, carcass traits, blood serum parameters and abdominal fatty acid composition of ducks was examined. One hundred day-old Turkish native duck chicks were divided into two groups, each with five replicates and given the same diets with 0 and 200 mg/l carnitine chlorhydrate via drinking water. The study lasted 8 weeks, with the first 4 weeks as a starter and the last 4 weeks as grower period. At the end of the study five ducks were randomly selected from each subgroup for slaughter. Growth performance parameters of ducks were not affected significantly by L-carnitine administration. Live weight, daily weight gain, cumulative feed consumption and average feed conversion efficiency were found to be 1490 and 1621 g, 26.0 and 28.1 g, 5386 and 5662 g, 3.75 and 3.54 kg/kg in the control and in the carnitine groups respectively. L-carnitine administration did not effect carcass traits and serum cholesterol, total lipid, triglyceride and glucose levels. Total saturated fatty acid content of abdominal fat significantly decreased, mono- and polyunsaturated fatty acid content were not affected by L-carnitine administration. In conclusion, L-carnitine administration by drinking water did not affect growth performance, carcass traits and blood parameters in ducks.

Determinants of Cliff Edge and Escape Responses in Herring Gull Chicks in Nature1)2)

AbstractHerring gull chicks from nests on a) cliff ledges and b) vegetated plateaus showed different types of escape and edge response when tested on an elevated platform. The birds from cliff sites, though bolder at the platform edge, were more reluctant to jump. Those from the plateau nests leapt to the ground with relatively little hesitation. Chicks from cliff eggs, hatched and reared in the plateau by foster parents, resembled native plateau chicks in their escape responses while chicks of plateau origin reciprocally transplanted to and reared on cliff sites showed the reluctance typical of cliff chicks. The posssibility of two genetic types reproductively isolated on the two breeding situations is thus essentially eliminated. The likelihood of a stable genetic polymorphism is considered and tentatively discarded as less plausible than an explanation based on learning. Although conditions favorable for simple instrumental conditioning along divergent lines are present in the two rearing situations, a theory is favored which attributes the divergence to major differences in the amount and variety of experience afforded by the two environments. Modest support for this theory is provided by experiments in which plateau chicks confined by fencing to the immediate nest vicinity tended to resemble the naturally deprived cliff chicks in their reluctance to jump. In conclusion the concept of species-characteristic responses is considered inapplicable to the cliff edge and escape patterns of herring gull chicks except as it incorporates recognition of a determining role in factors of the rearing environment.