1,720,984 research outputs found
Performance and feeding behaviour of group–housed rabbits with free or time–limited access to feed
No full textThe present study aimed at evaluating the effect of the feeding system (AL: ad libitum vs. R: time–based feed restriction) on performance, feeding behaviour and slaughter results in group–housed growing rabbits. A total of 288 crossbred rabbits of both sexes were housed in 18 pens (16 animals per pen), half fed ad libitum and half restricted during the first 3 weeks, and controlled from weaning to slaughter (33 to 75 d of age). At the beginning of the trial, R rabbits had access to feeder for 10 h a day; feeding time increased by 1 h every 3–4 d until 16 h/d in the first three weeks; then, feeding time increased by 1 h/d until 24–h access to feeders in the 4th week; thereafter, all animals were fed ad libitum. Rabbit feeding behaviour was controlled at 39, 46, 53 and 60 d of age by weighing the feeders every hour by an automatic weighing system. Individual data (live weight, carcass data) were analysed by PROC MIXED of SAS with the feeding system as fixed effect and the pen as a random effect; pen data (feed intake and conversion) were analysed by PROC GLM of SAS.
During the whole trial, AL rabbits exhibited small and frequent meals during all the day with minimum intakes (about 2–3 g/h) in the morning (9:00 to 11:00 h) and maximum intakes (7–10 g/h) in the evening (19:00 to 21:00 h). R rabbits showed higher hourly feed consumption than AL rabbits, with peaks of 18, 15 and 14 g in the first hour after accessing feeder at 39, 46 and 53 d of age when the feeding time was 11, 13 and 16 h/d, respectively. Once fed freely, R rabbits took only two days to reach the same intake pattern of AL rabbits.
In the first three weeks, feed intake was lower (–5%, i.e. 128 vs. 122 g/d; P<0.01) and feed conversion was better (–5%, i.e. 2.42 vs. 2.29; P<0.001) in R rabbits compared to AL ones. In the following 3 weeks, R rabbits showed a worse feed conversion than AL rabbits (+ 5%, i.e. 2.70 vs. 2.83; P<0.001). In the whole trial, the feeding system did not affect health status, growth performance, slaughter weight (on average 2860 g), dressing percentage (61.0%) and carcass and meat quality traits.
In conclusion, feeding behaviour was heavily affected by the restriction program, but rabbits returned quickly to a normal behaviour once fed freely. The time–restriction program in the first three weeks reduced feed intake level at 95% of ad libitum without compromising growth performance and slaughter results
Effect of Genotype, Gender, and Feed Restriction on Slaughter Results and Meat Quality of Broiler Chickens
Full text linkSlaughter results and meat quality were evaluated in 768 broilers according to genotype (standard breast yield vs. high breast yield), gender, and feeding systems
(ad libitum vs. feed restriction from 13 to 21 d of age). Standard-yield chickens had higher carcass weights (2358 g vs. 2319 g; P < 0.001) and hind legs proportion (31.1%
vs. 30.6%; P < 0.01), and lower dressing out percentage (73.6% vs. 74.0%; P < 0.01) compared to high-yield birds, besides lower meat L* index (45.3 vs. 46.2; P < 0.05),
higher final pH (5.89 vs. 5.85; P < 0.05) and thawing losses (10.5% vs. 9.43%; P < 0.05). Males showed higher carcass weight (+24%), dressing percentage (+0.7%), and hind leg yield (+4%) (P < 0.001) than females. Restricted birds had lower carcass weight (–2%; P < 0.001) and dressing percentage (-0.3%) (P < 0.05) than those always fed ad libitum. As what concerns meat quality, gender and feeding system aff ected only meat final pH, lower in ad libitum group than in restricted one and in females than males. In conclusions, slaughter results and carcass traits changed especially with genotype and gender, coherently with slaughter weight whereas meat quality was mostly
affected by genotype
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Feed restriction strategies in growing rabbits fed post-weaning diets with different protein levels
No full textThe present study evaluated the effects of the feeding system (AL: ad libitum vs. R1: monophasic feed restriction vs. R2: biphasic feed restriction) and the dietary crude protein (CP) level (HP: 16% CP vs. LP: 14% CP) on growth performance and slaughter yield of 336 crossbred growing rabbits reared from weaning to slaughtering (33–78 d of age) in 48 collective pens (7 rabbits/pen; 8 pen/group). The access time to feeders decreased from 16 to 9 h/d in the first week of trial in both R groups; it was 8 h/d given in a single slot (R1 group) or in two slots (R2 group: 4 h + 4 h separated by 4 h without feed access) during the 2nd and 3rd week. Then, access time increased to 12 h/d during the 4th week and, thereafter, it was 12 h/d in a single slot of access for both R groups until the end of the trial. The HP and LP diets were administered from 33 to 60 d of age, then the same fattening diet (14% CP) was provided to all groups. Data were analysed by ANOVA using PROC GLM procedure of SAS software. In the first period (33–61 d), both R groups showed lower daily weight gain (DWG) and feed intake (DFI) and better feed conversion (FC) compared to AL group (p < 0.001). In the second period (61–78 d), R rabbits maintained a lower DFI (p = 0.02) compared to AL rabbits but showed a higher DWG (p < 0.001) and a better FC (p < 0.001). At the end of the trial, there were no differences on growth performance among groups, whereas both R systems improved FC compared to AL one (p < 0.001). The R2 group had better FC than R1 during the 2nd and 3rd week. However, the differences between R1 and R2 groups disappeared in the following weeks- with the return to the monophasic system. At slaughtering, R rabbits had decreased carcass yield (p < 0.001) compared to the AL ones. The use of LP diet decreased DWG (p < 0.001) and increased FC (p < 0.001) in the first period. However, in the second period, LP rabbits achieved a higher DWG (p = 0.01) and a better FC (p = 0.01) compared to HP rabbits. At the end of the trial, LP and HP rabbits showed similar growth performance and slaughter results. Finally, no significant interaction was found between feeding system and dietary protein level. In conclusion, the application of feed restriction systems improved rabbit feed efficiency but significantly decreased slaughter yield compared to the AL system. The dietary CP level can be reduced until 14% in the post-weaning diets without negative effects on growth performance and slaughter yield
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Effect of age on caecal microbiota of broiler chickens fed diets supplemented with sodium butyrate
No full textA total of 768 chicks Ross 308 (half males and half females) were housed in 16 pens (48 animals/pen); half pens received a control diet, the other half the same diet supplemented with 150 mg microencapsulated Na-butyrate/kg diet. Growth performance was monitored until 45 d of age. At 11 d, 24 d, and 35 d of age, 32 animals per age were slaughtered to sample caecal content. Intestinal microbiota was evaluated by sequencing of V3-V4 region
of the rRNA 16S gene using Miseq Illumina. Firmicutes was the most represented phylum, followed by Tenericutes and Proteobacteria; Bacteroidates was the least represented. Out of classes, Clostridia was prevalent, followed by Bacilli and Grammaproteobacteria. The dietary Na-butyrate supplementation did not affect performance: final live weight averaged 3294 and 3266 g in the control and supplemented group, respectively, corresponding to 113 and 112 g/d feed intake, and 1.44 and 1.43 feed conversion ratio. The dietary treatment did not affect the composition or abundance neither the diversity of gut microbiota. Only some OTUs (26) had different distributions according to dietary treatment (P<0.05): some, mostly belonging
to Firmicutes phylum and to Clostridiales order, were more abundant in samples from birds fed the control diet; others, such as Tenericutes of the RF39 order, were more present in samples from chickens supplemented with Na-butyrate. On the other hand, microbiota composition significantly changed with age (P=0.001). Among phyla, Proteobacteria and Firmicutes decreased as age increased, whereas Tenericutes increased from 11 to 24 d of age.
Among classes, Mollicutes, X4C0d2, Bacterioidia, and Clostridia increased, whereas Grammaproteobacteria decreased with age. Among orders, Lactobacillales, Enterobacteriales, Erysipelotrichales, burkholderiales, Oceanospirillales, Alteromonadales, Pseudomonadales, Pasteurellales, and Unclassified beta Proteobacteria decreased. The biodiversity in each sample and among samples tended to decrease when age increased. The
effect on biodiversity among samples was evident using both qualitative analysis (that considers presence/absence of sequences and phylogenetic distances) and quantitative analysis (that considers only sequence abundance). The results of the present study indicate that Na-supplementation did not affect caecal microbiota. On the other hand, bacterial groups of gut community decreased with age and the community became more similar among
samples
- …
