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Fulltext The Effects of Feed Restriction and Isolated or Group Rearing on the Measurement of Individual Feed Intake and Estimation of Feed Conversion Ratio in Juvenile Nile Tilapia (Oreochromis niloticus) for Selective Breeding Purposes

Rodde C, Vandeputte M, Trinh TQ, Douchet V, Canonne M, Benzie JAH, et al.

Front Genet, 2020;11:596521.
PMID: 33519898 DOI: 10.3389/fgene.2020.596521

Accurately measuring the phenotype at the individual level is critical to the success of selective breeding programs. Feed efficiency is a key sustainability trait and is typically approached through feed conversion ratio (FCR). This requires measurements of body weight gain (BWG) and feed intake (FI), the latter being technically challenging in fish. We assessed two of the principal methods for measuring feed intake in fish over consecutive days: (1) group rearing 10 fish per group and video recording the meals and (2) rearing fish individually on a restricted ration. Juvenile Nile tilapia (Oreochromis niloticus) from the Genetically Improved Farmed Tilapia (GIFT) strain and the Cirad strain were entered into the study (128 GIFT and 109 Cirad). The GIFT strain were reared over three consecutive periods of 7 days each under different feeding, recording, and rearing scenarios (i) in groups fed an optimal ration (g100) or (ii) fed a 50% restricted ration (g50) both with video records of all meals and (iii) reared in isolation and fed a 50% restrictive ration. The Cirad strain were tested similarly but only for scenarios (i) and (iii). All fish were fed twice daily with a calculated ration. Correlations showed the same trends for the GIFT and the Cirad strains. For the GIFT strain, correlations were positive and significant for BWG and FI measured in scenarios (i) and (ii), 0.49 and 0.63, respectively, and FI measured in scenarios (i) and (iii) (0.50) but not for BWG measured in scenarios (i) and (iii) (0.29, NS). The phenotypic correlation estimated for FCR between scenarios (i) and (ii) with fish fed an optimal or a 50% restricted ration was low and not significant (0.22). Feed Conversion Ratio for GIFT fish reared in groups or in isolation and fed with a restricted ration [scenarios (ii) and (iii)] were not significantly correlated either. Social interactions between fish, potentially impacting their efficiency, may explain the results. Therefore, selective breeding programs seeking to improve feed efficiency will need to carefully plan the feeding rate and the rearing system used to estimate FCR in order to optimize selection for the targeted production system.
Fulltext Quantifying the genetic parameters of feed efficiency in juvenile Nile tilapia Oreochromis niloticus

de Verdal H, Vandeputte M, Mekkawy W, Chatain B, Benzie JAH

BMC Genet, 2018 11 16;19(1):105.
PMID: 30445908 DOI: 10.1186/s12863-018-0691-y

BACKGROUND: Improving feed efficiency in fish is crucial at the economic, social and environmental levels with respect to developing a more sustainable aquaculture. The important contribution of genetic improvement to achieve this goal has been hampered by the lack of accurate basic information on the genetic parameters of feed efficiency in fish. We used video assessment of feed intake on individual fish reared in groups to estimate the genetic parameters of six growth traits, feed intake, feed conversion ratio (FCR) and residual feed intake in 40 pedigreed families of the GIFT strain of Nile tilapia, Oreochromis niloticus. Feed intake and growth were measured on juvenile fish (22.4 g mean body weight) during 13 consecutive meals, representing 7 days of measurements. We used these data to estimate the FCR response to different selection criteria to assess the potential of genetics as a means of increasing FCR in tilapia.
RESULTS: Our results demonstrate genetic control for FCR in tilapia, with a heritability estimate of 0.32 ± 0.11. Response to selection estimates showed FCR could be efficiently improved by selective breeding. Due to low genetic correlations, selection for growth traits would not improve FCR. However, weight loss at fasting has a high genetic correlation with FCR (0.80 ± 0.25) and a moderate heritability (0.23), and could be an easy to measure and efficient criterion to improve FCR by selective breeding in tilapia.
CONCLUSION: At this age, FCR is genetically determined in Nile tilapia. A selective breeding program could be possible and could help enabling the development of a more sustainable aquaculture production.
Fulltext An investigation of links between metabolic rate and feed efficiency in European sea bass Dicentrarchus labrax

Rodde C, de Verdal H, Vandeputte M, Allal F, Nati J, Besson M, et al.

J Anim Sci, 2021 Jun 01;99(6).
PMID: 33966070 DOI: 10.1093/jas/skab152

Feed efficiency (FE) is the amount of body weight gain for a given feed intake. Improving FE through selective breeding is key for sustainable finfish aquaculture but its evaluation at individual level is technically challenging. We therefore investigated whether individual routine metabolic rate (RMR) was a predictor of individual FE in the European sea bass Dicentrarchus labrax, a major species in European mariculture. The European sea bass has three genetically distinct populations across its geographical range, namely Atlantic (AT), West Mediterranean (WM), and East Mediterranean (EM). We compared FE and RMR of fish from these three populations at 18 or 24 °C. We held 200 fish (62 AT, 66 WM, and 72 EM) in individual aquaria and fed them from ad libitum down to fasting. FI was assessed for an ad libitum feeding rate and for a fixed restricted ration (1% of metabolic body weight·day-1, with metabolic body weight = body weight0.8). After being refed 12 wk in a common tank, individual RMR was measured over 36 h by intermittent flow respirometry. There was a significant effect of temperature whereby fish at 18 °C had greater mean FE (P < 0.05) and lower RMR (P < 0.001). There was also a significant effect of population, where AT fish had lower FE (P < 0.05) and greater RMR (P < 0.001) than WM and EM, at both temperatures. Despite these differences in temperature and population means, individual FE and RMR were not significantly correlated (P > 0.05). Therefore, although the results provide evidence of an association between metabolic rate and FE, RMR was not a predictor of individual FE, for reasons that require further investigation.
30-day morbidity and mortality of revisional bariatric surgery - An international multi-centre collaborative (BROAD) study

Nasta AM, Goel R, Singhal R, Lemmens L, Baig S, Seki Y, et al.

Obes Res Clin Pract, 2024;18(3):195-200.
PMID: 38955573 DOI: 10.1016/j.orcp.2024.06.001

INTRODUCTION: Revisional bariatric surgery (RBS) for insufficient weight loss/weight regain or metabolic relapse is increasing worldwide. There is currently no large multinational, prospective data on 30-day morbidity and mortality of RBS. In this study, we aimed to evaluate the 30-day morbidity and mortality of RBS at participating centres.
METHODS: An international steering group was formed to oversee the study. The steering group members invited bariatric surgeons worldwide to participate in this study. Ethical approval was obtained at the lead centre. Data were collected prospectively on all consecutive RBS patients operated between 15th May 2021 to 31st December 2021. Revisions for complications were excluded.
RESULTS: A total of 65 global centres submitted data on 750 patients. Sleeve gastrectomy (n = 369, 49.2 %) was the most common primary surgery for which revision was performed. Revisional procedures performed included Roux-en-Y gastric bypass (RYGB) in 41.1 % (n = 308) patients, One anastomosis gastric bypass (OAGB) in 19.3 % (n = 145), Sleeve Gastrectomy (SG) in 16.7 % (n = 125) and other procedures in 22.9 % (n = 172) patients. Indications for revision included weight regain in 615(81.8 %) patients, inadequate weight loss in 127(16.9 %), inadequate diabetes control in 47(6.3 %) and diabetes relapse in 27(3.6 %). 30-day complications were seen in 80(10.7 %) patients. Forty-nine (6.5 %) complications were Clavien Dindo grade 3 or higher. Two patients (0.3 %) died within 30 days of RBS.
CONCLUSION: RBS for insufficient weight loss/weight regain or metabolic relapse is associated with 10.7 % morbidity and 0.3 % mortality. Sleeve gastrectomy is the most common primary procedure to undergo revisional bariatric surgery, while Roux-en-Y gastric bypass is the most commonly performed revision.