Robotic Versus Laparoscopic Hepatectomy: A Single Surgeon Experience of 629 Consecutive Minimally Invasive Liver Resections

BACKGROUND

Robotic surgery has the potential to broaden the indications for minimally invasive liver surgery owing to its technical advantages. This paper compares our experience with robotic liver surgery (RLS) with conventional laparoscopic liver surgery (LLS).

METHODS

All consecutive liver resections between October 2011 and October 2022 were selected from our prospective database to be included in this cohort study. Patients who underwent RLS were compared with a LLS group for operative and postoperative outcomes.

RESULTS

In total, 629 patients were selected from our database, including 177 patients who underwent a RLS and 452 patients who had LLS. Colorectal liver metastasis was the main indication for surgery in both groups. With the introduction of RLS, the percentage of open resections decreased significantly (32.6% from 2011 to 2020 vs. 11.5% from 2020 onward, P < 0.001). In the robotic group, redo liver surgery was more frequent (24.3% vs. 16.8%, P = 0.031) and the Southampton difficulty score was higher (4 [IQR 4 to 7] vs. 4 [IQR 3 to 6], P = 0.02). Median blood loss was lower (30 vs. 100 ml, P < 0.001), and postoperative length of stay (LOS) was shorter in the robotic group (median 3 vs. 4 days, P < 0.001). There was no significant difference in postoperative complications. Cost related to the used instruments and LOS was significantly lower in the RLS group (median €1483 vs. €1796, P < 0.001 and €1218 vs. €1624, P < 0.001, respectively), while cost related to operative time was higher (median €2755 vs. €2470, P < 0.001).

CONCLUSIONS

RLS may allow for a higher percentage of liver resections to be completed in a minimally invasive way with lower blood loss and a shorter LOS.

Combined Ablation and Resection for Colorectal Liver Metastases in the Minimally Invasive Surgical Era

BACKGROUND

Thermal ablation is an accepted treatment modality for small and central liver tumors. In extensive colorectal liver metastatic disease (CRLM), hepatectomy can be combined with ablation, resulting in a parenchymal-sparing strategy. This may increase salvageability rates in case of recurrence.

METHODS

All patients with advanced CRLM that underwent combined ablation and resection between April 2012 and April 2021, were retrospectively analyzed from a prospectively maintained database. Primary endpoints include postoperative 30-day morbidity and ablation-site recurrence (ASR). The surgical approaches were compared. Ablated lesions were screened for ASR on postoperative follow-up imaging.

RESULTS

Of 54 patients that underwent combined ablation and resection, 32 (59.3%) were performed through a minimally invasive approach. Eleven (20.4%) were minor resections, 32 (59.3%) were technically major and 11 (20.4%) were anatomically major resections. Twelve complications occurred (22.2%), among which 2 (3.8%) major complications (Clavien-Dindo ≥IIIa). Ninety-day mortality rate was 1.9%. Out of 82 ablated lesions, 6 ASRs (11.1%) occurred. Median blood loss was significantly lower in the minimally invasive group, compared with open [90 mL (32.5 to 200) vs. 200 mL (100 to 400), P =0.005]. Pringle maneuver was significantly performed less in the minimally invasive group [8 (25.0%) vs. 16 (72.7%), P =0.001], but took more time [36.1 min (±15.6) vs. 21.6 (±9.9); P =0.011]. Short-term (1 y) overall and disease-free survival were respectively 81.4% and 50.0%.

CONCLUSION

Combining microwave ablation and liver resection is a feasible and safe parenchymal-sparing technique, through both minimally invasive and open approach for treating extended CRLM disease. It has a low ablation-related complication rate and acceptable ablation-site recurrence rate.

Transition from laparoscopic to robotic liver surgery: clinical outcomes, learning curve effect, and cost-effectiveness

The reproducibility of the implementation of robotic liver surgery (RLS) is still debated. The aim of the present study is to evaluate short-term outcomes and cost differences during the implementation of RLS, performed by an early adopter in laparoscopic liver surgery (LLS). Patients undergoing RLS between February 2020 and May 2021 were included. Short-term outcomes of the robotic group (RG) were compared to the "Initial Phase" group (IP) of 120 LLS cases and the 120 most recent laparoscopic cases or "Mastery Phase" group (MP). A cost analysis per procedure for the three groups was performed. Seventy-one patients underwent RLS during the study period. Median operative time in the RG was comparable to the IP, but significantly shorter in the MP (140 vs 138 vs 120 min, p < 0.001). Median intraoperative blood loss in the RG was lower than in both laparoscopic groups (40 ml [20-90 ml] vs 150 ml [50-250 ml] vs 80 ml [30-150 ml], p < 0.001). Median hospital stay in the RG was significantly shorter than the IP group (p < 0.001). There were no significant differences in postoperative complication, conversion, or readmission rates. Procedural cost analysis was in favor of robotic surgery (€5008) compared to the IP (€ 6913) and the MP (€6099). Surgeons with sufficient experience in LLS can rapidly overcome the learning curve for RLS. In our experience, the short-term outcomes of the implementation phase of RLS are similar to the mastery phase of LLS. The total average cost per procedure is lower for RLS compared to LLS.

Laparoscopic versus open liver resection for intrahepatic cholangiocarcinoma: a multicenter propensity score-matched study

BACKGROUND

The role of laparoscopy in the treatment of intrahepatic cholangiocarcinoma (ICC) remains unclear. This multicenter study examined the outcomes of laparoscopic liver resection for ICC.

METHODS

Patients with ICC who had undergone laparoscopic or open liver resection between 2012 and 2019 at four European expert centers were included in the study. Laparoscopic and open approaches were compared in terms of surgical and oncological outcomes. Propensity score matching was used for minimizing treatment selection bias and adjusting for confounders (age, ASA grade, tumor size, location, number of tumors and underlying liver disease).

RESULTS

Of 136 patients, 50 (36.7%) underwent laparoscopic resection, whereas 86 (63.3%) had open surgery. Median tumor size was larger (73.6 vs 55.1 mm, p = 0.01) and the incidence of bi-lobar tumors was higher (36.6 vs 6%, p < 0.01) in patients undergoing open surgery. After propensity score matching baseline characteristics were comparable although open surgery was associated with a larger fraction of major liver resections (74 vs 38%, p < 0.01), lymphadenectomy (60 vs 20%, p < 0.01) and longer operative time (294 vs 209 min, p < 0.01). Tumor characteristics were similar. Laparoscopic resection resulted in less complications (30 vs 52%, p = 0.025), fewer reoperations (4 vs 16%, p = 0.046) and shorter hospital stay (5 vs 8 days, p < 0.01). No differences were found in terms of recurrence, recurrence-free and overall survival.

CONCLUSION

Laparoscopic resection seems to be associated with improved short-term and with similar long-term outcomes compared with open surgery in patients with ICC. However, possible selection criteria for laparoscopic surgery are yet to be defined.

Guidelines on Standard and Therapeutic Diets for Adults in Hospitals by the French Association of Nutritionist Dieticians (AFDN) and the French Speaking Society of Clinical Nutrition and Metabolism (SFNCM)

AIM

Hospital food provision is subject to multiple constraints (meal production, organization, health safety, environmental respect) which influence the meal tray offered to the patient. Multiple diets can add complexity and contribute to non-consumption of the meal. To avoid undernutrition, it appeared necessary to propose guidelines for foods and diets in hospitals.

METHODS

These guidelines were developed using the Delphi method, as recommended by the HAS (French Health Authority), based on a formal consensus of experts and led by a group of practitioners and dieticians from the AFDN (French Association of Nutritionist Dieticians) and SFNCM (French Society of Clinical Nutrition and Metabolism).

RESULTS

Twenty-three recommendations were deemed appropriate and validated by a panel of 50 national experts, following three rounds of consultations, modifications and final strong agreement. These recommendations aim to define in adults: 1-harmonized vocabulary related to food and diets in hospitals; 2-quantitative and qualitative food propositions; 3-nutritional prescriptions; 4-diet patterns and patient adaptations; 5-streamlining of restrictions to reduce unnecessary diets and without scientific evidence; 6-emphasizing the place of an enriched and adapted diet for at-risk and malnourished patients.

CONCLUSION

These guidelines will enable catering services and health-care teams to rationalize hospital food and therapeutic food prescriptions in order to focus on individual needs and tasty foods. All efforts should be made to create meals that follow these recommendations while promoting the taste quality of the dishes and their presentation such that the patient rediscovers the pleasure of eating in the hospital.

One-stage laparoscopic parenchymal sparing liver resection for bilobar colorectal liver metastases: safety, recurrence patterns and oncologic outcomes

BACKGROUND AND PURPOSE

Laparoscopic liver resections (LLR) of bilobar colorectal liver metastases (CRLM) are challenging and the safety and long-term outcomes are unclear. In this study, the short- and long-term outcomes and recurrence patterns of one-stage LLR for bilobar CRLM were compared to single laparoscopic resection for CRLM.

METHODS

This single-center study consisted of all patients who underwent a parenchymal sparing LLR for CRLM between October 2011 and December 2018. Demographics, perioperative outcomes, short-term outcomes, oncologic outcomes and recurrence patterns were compared. Data were retrieved from a prospectively maintained database.

RESULTS

Thirty six patients underwent a LLR for bilobar CRLM and ninety patients underwent a single LLR. Demographics were similar among groups. More patients received neoadjuvant chemotherapy in the bilobar group (55.6% vs 34.4%, P = 0.03). There was no difference in conversion rate, R0 resection and transfusion rate. Blood loss and operative time were higher in the bilobar group (250 ml (IQR 150-450) vs 100 ml (IQR 50-250), P < 0.001 and 200 min (IQR 170-230) vs 130 min (IQR 100-165), P < 0.001) and hospital stay was longer (5 days (IQR 4-7) vs 4 days (IQR 3-6), P = 0.015). The bilobar group had more technically major resections (88.9% vs 56.7%, P < 0.001). Mortality was nil in both groups and major morbidity was similar (2.8% vs 3.3%, P = 1.0). There was no difference in recurrence pattern. Overall survival (OS) was similar (1 yr: 96% in both groups and 5 yr 76% vs 66%, P = 0.49), as was recurrence-free survival (RFS) (1 yr: 64% vs 73%, 3 yr: 38 vs 42%, 5 yr: 38% vs 28%, P = 0.62).

CONCLUSION

In experienced hands, LLR for bilobar CRLM can be performed safely with similar oncologic outcomes as patients who underwent a single LLR for CRLM.

Five-year single center experience of sacral neuromodulation for isolated fecal incontinence or fecal incontinence combined with low anterior resection syndrome

PURPOSE

Sacral neuromodulation (SNM) has proven to be a safe and effective treatment for fecal incontinence (FI). For low anterior resection syndrome (LARS), however, SNM efficacy is still poorly documented. The primary aim of this study was to report on efficacy of SNM therapy for patients with isolated FI or LARS. Furthermore, we evaluated the safety of the procedure and the relevance of adequate follow-up.

METHODS

A retrospective analysis was performed upon a prospectively maintained database of all patients who underwent SNM therapy for isolated FI or LARS between January 2014 and January 2019. The Wexner and LARS scores were evaluated at baseline, during test phase, after definitive implantation and annually during follow-up. Treatment success was defined as at least 50% improvement of the Wexner score or a reduction to minor or no LARS.

RESULTS

Out of 89 patients with isolated FI or LARS who had a SNM test phase, 62 patients were eligible for implantation of the permanent SNM device. At baseline, 3 weeks, and 1, 2, 3, 4 and 5 years after definitive implantation the median Wexner score of all patients was 18, 2, 4.5, 5, 5, 4 and 4.5, respectively, and 18, 4, 5.5, 5, 4, 3 and 4, respectively, for patients with FI and LARS. Patients with LARS more frequently required changes in program settings.

CONCLUSIONS

SNM therapy is a safe and effective treatment for patients with isolated FI and patients with FI and LARS. Adequate follow-up is essential to ensure long-term effectivity, especially for LARS patients.

A multicenter cohort analysis of laparoscopic hepatic caudate lobe resection

INTRODUCTION

Laparoscopic resection of the hepatic caudate lobe (LRCL) requires a high level of expertise due to its challenging anatomical area. Only case reports, case series, and single-center cohort studies have been published. The aim of this study was to assess the safety and feasibility of this laparoscopic procedure.

METHODS

A multicenter retrospective cohort study including all patients who underwent LRCL in 4 high-volume hepatobiliary units between January 2000 and May 2018 was performed. Perioperative, postoperative, and survival outcomes were assessed. Postoperative morbidity was stratified according to the Clavien-Dindo classification with severe complications defined by grade III or more. The Kaplan-Meier method was used for survival analysis.

RESULTS

A total of 32 patients were included, including 22 (68.8%) with colorectal liver metastasis (CRLM), one (3.1%) with cholangiocarcinoma, four (12.5%) with other malignancies, and five (15.6%) with symptomatic benign lesions. Simultaneous colorectal and/or additional liver resection was performed in 20 (62.5%) patients. The median (IQR) operative time was 155 (121-280) minutes, blood loss was 100 (50-275) ml, conversion rate was 9.4% (n = 3), severe complications were observed in 2 patients (6.3%), and median (range) length of hospital stay was 3 [1-39] days. No 90-day postoperative mortality was noticed. The median (IQR) follow-up for the CRLM group was 14 [10-23] months. Five-year overall survival rate was 82% in this subgroup. Small interinstitutional differences were observed without major impact on surgical outcomes.

CONCLUSION

LRCL is safe and feasible when performed in high-volume centers. Profound anatomical knowledge, advanced laparoscopic skills, and mastering intraoperative ultrasound are essential. No major interinstitutional differences were ascertained.

Stepwise implementation of laparoscopic pancreatic surgery. Case series of a single centre's experience

BACKGROUND

Laparoscopic pancreatic surgery still represents a challenge for surgeons. However, in recent decades the experience is expanding. Recent systematic reviews and meta-analyses confirm that laparoscopic pancreatic resection (LPR) is safe, feasible and worthwhile. This study analyses the first 100 consecutive LPRs in our centre.

METHODS

A retrospective analysis was conducted of the first 100 LPRs in a single supra-regional Belgian centre, performed between January 2012 and January 2019. Pre-, peri- and postoperative data were retrieved from a prospectively maintained database. All procedures were performed laparoscopically by two attending surgeons, specialized in minimally invasive and hepatopancreatobiliary surgery.

RESULTS

Of 100 procedures, 62 laparoscopic pancreatoduodenectomies (LPD) and 36 laparoscopic distal pancreatectomies (LDP) were performed, along with 1 enucleation and 1 central pancreatectomy. Indication was malignancy in 70%. Conversion rate was 24,2% in LPD and 11% in LDP. Median operative time was 330 min (IQR 300-360) in LPD and 150 min (IQR 142.5-210) in LDP. Median blood loss was 200 mL (IQR 100-487.5) in LPD and 150 mL (IQR 50-500) in LDP, transfusion rate was 22.6% and 8.3% respectively. Median length of stay (LOS) was 13 days (IQR 10-19.25) in LPD and 9 days (IQR 9-14) in LDP. R0 resection rate was 88.6% (62/70). Major complication rate (Clavien-Dindo grade III-IV) was 12%. Thirty-day mortality was 0%, 90-day mortality was 2%.

CONCLUSION

Our results confirm that LPR is a feasible and safe alternative to open pancreatic surgery. Safe implementation with a clear strategy is fundamental to gain experience and overcome the learning curve of this technically demanding procedures.

Perioperative radiotherapy is an independent risk factor for major LARS: a cross-sectional observational study

PURPOSE

Sphincter-preserving surgery for rectal cancer is often associated with low anterior resection syndrome (LARS). The aim of our study was to determine the prevalence of LARS in our institution and identify possible risk factors for LARS. Furthermore, we evaluated which of the LARS symptoms was considered most disabling by patients and whether or not there is an adaptation of the LARS score over time.

METHODS

This study includes a prospective database of 100 patients who underwent total or partial mesorectal excision between January 2009 and September 2014. Patients were contacted after a median postoperative time of 38 (5-45) months to determine the LARS score and to identify LARS symptoms that were considered most disabling. Uni- and multivariate regression analysis was performed to identify risk factors for LARS and major LARS. Finally, the LARS score was evaluated over time after restoration of bowel continuity.

RESULTS

Out of the 100 patients, 16 had minor LARS (score 21-29) and 51 patients had major LARS (score 30-42). Radiotherapy was an independent risk factor for major LARS (p = 0.04). For the majority of patients with major LARS (22%), fragmentation was considered the most disabling complaint. There was no correlation between interval after restoration of bowel continuity and the severity of the LARS score.

CONCLUSIONS

Perioperative radiotherapy is an independent risk factor for major LARS. Fragmentation is considered the most disabling complaint in the majority of patients with major LARS. There is no significant adaptation of the LARS score over time.

The Effectiveness of a Clinical Pathway in Liver Surgery: a Case-Control Study

BACKGROUND

In the field of liver surgery, evidence on the effectiveness of clinical pathways based on ERAS principles is limited.

METHODS

This is a single-center observational study from a prospectively maintained database. Two cohorts were formed of all patients undergoing liver surgery during a defined period before (traditional management) and after introduction of a clinical pathway. Additionally, a case-match analysis-based on approach, tumor location, and Brisbane classification of resection-was performed. A cost analysis and patient satisfaction questionnaire were carried out.

RESULTS

In both the overall analysis (n = 229) as well as the case-match analysis (n = 100), hospital stay was significantly reduced from 8 to 4 days and from 6.5 to 4 days, respectively (p < 0.05). Postoperative morbidity (traditional management 11/50 vs clinical pathway 5/50; p = 1.00) and readmission rate did not increase. Cost analysis showed a significant decrease in postoperative costs in favor of the clinical pathway (traditional management €3666.7 vs clinical pathway €1912.2; p < 0.001). Overall, 92.3% of the survey questions were answered with satisfied (86.0%) or very satisfied (6.3%).

DISCUSSION

Implementation of clinical pathway for liver surgery is feasible and safe. A clinical pathway significantly reduces hospital stay without increasing postoperative morbidity and readmission rates. Postoperative costs are significantly reduced. Patient satisfaction is high.

Sacral neurostimulation for low anterior resection syndrome after radical resection for rectal cancer: evaluation of treatment with the LARS score

PURPOSE

Sacral neurostimulation (SNS) has proven to be an effective treatment modality for low anterior resection syndrome (LARS). The primary aim of this study is to investigate the impact of SNS on all symptoms of LARS, not merely on fecal incontinence. Furthermore, we wanted to evaluate whether the LARS score could be useful as a tool to evaluate SNS treatment.

METHODS

All patients diagnosed with minor or major LARS, unresponsive to conservative therapy for fecal incontinence, who underwent sacral neuromodulation for LARS at Groeninge Hospital, Kortrijk, Belgium, were prospectively enrolled in the study. The primary endpoint was the reduction in the severity of LARS. This was assessed by validated questionnaires: the LARS score and the Wexner score.

RESULTS

Eleven patients underwent definite implantation of the SNS device. All patients showed a substantial decrease in their Wexner scores: The mean score was reduced from 17.7 to 4.6 (Z: 2.93; p: 0.0033). Additionally, the mean LARS score dropped from 36.9 to 11.4 (Z: 2.93; p: 0.0033). Furthermore, there was a significant amelioration of all symptoms of LARS.

CONCLUSIONS

Our study shows that SNS is effective for all symptoms of LARS. The authors believe that in patients who receive SNS for LARS, it could be useful to determine the LARS score to evaluate the complexity of the symptoms and their response to treatment.

Central Venous Pressure Drop After Hypovolemic Phlebotomy is a Strong Independent Predictor of Intraoperative Blood Loss During Liver Resection

BACKGROUND

Intraoperative hypovolemic phlebotomy (HP) has been suggested to reduce central venous pressure (CVP) before hepatectomy. This study aimed to analyze the impact of CVP drop after HP on intraoperative blood loss and postoperative renal function.

METHODS

A retrospective review of a prospective database including 100 consecutive patients (43 males and 57 females; mean age, 65 years; range 23-89 years) undergoing liver resection with HP was performed. The primary outcome variable was estimated blood loss (EBL), and the secondary outcome was postoperative serum creatinin (Scr). A multivariate linear regression analysis was performed to identify predictors of intraoperative blood loss.

RESULTS

The median CVP before blood salvage was 8 mmHg (range 4-30 mmHg). The median volume of hypovolemic phlebotomy was 400 ml (range 200-1000 ml). After HP, CVP decreased to a median of 3 mmHg (range -2 to 16 mmHg), resulting in a median CVP drop of 5.5 mmHg (range 2-14 mmHg). The median EBL during liver resection was 165 ml (range 0-800 ml). The median preoperative serum creatinin (Scr) was 0.82 g/dl (range 0.5-1.74 g/dl), and the postoperative Scr on day 1 was 0.74 g/dl (range 0.44-1.68 g/dl). The CVP drop was associated with EBL (P < 0.001). There was no significant impact of CVP drop on postoperative Scr.

CONCLUSION

A CVP drop after HP is a strong independent predictor of EBL during liver resection. The authors advocate the routine use of HP to reduce perioperative blood loss and transfusion rates in liver surgery. As a predictive tool, CVP drop might help surgeons decide whether a laparoscopic approach is safe.

Ovis aries POU1F1 Gene: Cloning, Characterization and Polymorphism Analysis

POU1F1 (PIT-1/GHF-1) is a transcription factor with critical role in the transcriptional regulation of multiple genes in the pituitary and also important for the survival, differentiation and proliferation of three pituitary cell types. To understand the regulation of POU1F1 gene in Ovis aries we report its cloning, sequencing and characterization. The sequenced 5787 bp included six exons and two complete introns. Ovine POU1F1 gene has a high level of conservation with its bovine, human and rat counterparts showing 98.2%, 91.2% and 86.2% of similarity at the coding level, respectively. All six exons were analyzed for polymorphism detection in 100 animals of the Portuguese indigenous ovine breed 'Churra da Terra Quente'. One polymorphism was found at codon 58 in exon 2, in one allele of 4 animals leading to a change from cysteine to tyrosine (2% allelic frequency). In exon 3 two polymorphisms were detected: a G to A transition altering a glycine to an asparagine at codon 89 in one allele of one animal (0.5% allelic frequency) and another G to A transition at codon 105 converting an alanine into a threonine in one allele of 3 animals (1.5% allelic frequency). These polymorphisms might change the structure of the POU1F1 protein and modify gene-expression. In intron 4, an A to G transition was detected in one allele of six animals (3% allelic frequency). Exons 1, 4 and 6 showed no polymorphisms.

Dexamethasone ester treatment alters insulin-like growth factor-I, its binding proteins and thyroid status in finishing calves

To improve carcass quality in finishing calves, some breeders use preparations containing corticoids alone or in association with other growth promoters. We have investigated the effects of dexamethasone treatment on insulin-like growth factor-I (IGF-I), IGF-binding proteins (IGFBP-2 and 3) and thyroid hormones (T3, T4, free T4). Limousine male calves were allocated to a control group (C) (n = 18) and a group (n = 18) that received dexamethasone esters (DEX). Blood and hepatic tissue samples were collected at slaughtering. Thyroid hormones and IGF-I plasma levels were measured by RIA and IGFBPs were evaluated by immunoblotting. Hepatic type I 5′deiodinase (5′D-I) activity was determined by enzyme assay and hepatic expression of mRNA for GH receptor, IGF-I, IGFBP-2, IGFBP-3 and type I deiodinase (D-I) was evaluated by dot blot analysis. Plasma IGF-I and IGFBP-3 levels were reduced by the DEX treatment (P < 0.001 and P < 0.01, respectively) while IGFBP-2 was unaffected. Significant plasma changes for IGF-I and IGFBP-3 were not corroborated by hepatic mRNA levels, for which only a slight non-significant decrease was noted. Growth hormone receptor mRNA expression was increased after treatment (P < 0.01). T3 plasma level was higher in DEX animals (P < 0.05) than in C calves. Finally, treatment increased 5′D-I activity in the hepatic tissue (P < 0.001) and seemed to also affect D-I mRNA expression (P = 0.1). In conclusion, dexamethasone ester injection in calves altered some of their endocrinological parameters; this could explain the catabolic action of corticoids in the bovine species. Key words: Calves, corticoids, IGF-I, IGFBPs, thyroid axis

A homologous radioimmunoassay for quantification of insulin-like growth factor-binding protein-2 in blood from cattle

Insulin-like growth factor-I and -II (IGF-I, IGF-II) circulate in biological fluids bound to six different IGF-binding proteins that regulate IGF bioactivity. The IGF-binding protein-2 is regulated by growth hormones, and its concentration depends on nutrition and physiological state. Specific antibodies directed against bovine IGF-binding protein-2 were produced, and IGF-binding protein-2 levels in bovine blood samples were quantified by radioimmunoassay. Parallel displacement curves showed strong cross-reactivity with bovine and ovine plasma, were low with porcine plasma, and no cross-reactivity with rat or chicken plasma. Addition of IGF-I or -II to a control pool of bovine plasma did not significantly alter control IGF-binding protein-2 values in a radioimmunoassay. Six nycthemeral periods, determined for three young bulls bled on two occasions, showed that IGF-binding protein-2 plasma levels were stable throughout the day; two or three samples were sufficient to characterize the animal. Cows treated with recombinant bovine somatotropin (bST) had significantly lower serum levels of IGF-binding protein-2 than did control cows. Furthermore, IGF-binding protein-2 levels were dramatically increased at the onset of lactation. This radioimmunoassay for bovine IGF-binding protein-2, which enables quantitative assessment of IGF-binding protein-2 concentration in cattle, confirmed that IGF-binding protein-2 concentrations are depressed by administration of bST, enhanced after calving, and showed absence of diurnal variation.

Feed restriction in young bulls alters the onset of puberty in relationship with plasma insulin-like growth factor-I (IGF-I) and IGF-binding proteins

The objectives of this study were to evaluate the effect of feed restriction and re-alimentation on the onset of puberty and IGF status in peripubertal male calves and to compare the radioimmunoassay (RIA) and western ligand blotting (WLB) methods for bovine IGFBP-2. Twelve prepubertal 290 d-old Belgian Blue bulls (mean weight: +/- 290 kg) were randomly assigned in three groups: a control group (NG; n = 4) receiving a classic fattening diet to induce "normal" growth (1.48 kg/d), a feed restricted group (RG; n = 4) to obtain reduced growth (0.50 kg/d) and, a severely restricted group (SG; n = 4) to nearly stop growth (0.08 kg/d). The feed restriction period was maintained over a period of 114 d. After the period of differential feeding, all animals received the control feed regime over a period of 100 d. Blood samples were collected at fortnightly intervals. Circulating IGF-I was measured by RIA whereas plasma IGFBPs was evaluated by WLB; IGFBP-2 was additionally quantified by RIA procedure. At the beginning of the trial, IGF-I levels were low (<100 ng/ml) and similar in the three groups in accordance with prepubertal status. In the NG group, a progressive rise in IGF-I was observed from Day 42 to Day 142 whereas in the RG and SG groups, IGF-I levels did not change until the experimental restriction period ended. The delay of the rise in plasma IGF-I was longer for the SG group, IGF-I remained low until 2 wk after the end of the period of restricted feeding. Surprisingly, although differences were detected for IGF-I levels between the three groups, the IGFBP-2 and -3 data, evaluated by WLB could only discriminate between NG and SG group and not between NG and RG. However, by using a RIA method, an IGFBP-2 decrease was observed in the NG group coincident with increasing IGF-I levels. For both RG and SG groups, IGFBP-2 levels remained high throughout the feed restriction period whereas plasma IGFBP-2 levels declined upon feeding in both groups. During this feed restriction period, IGFBP-2 was significantly lower in NG than in RG or SG groups. Moreover, SG group animals had higher levels in plasma IGFBP-2 than RG animals. In conclusion, puberty is characterized by developmental changes in plasma IGF-I and IGFBPs that were altered by feed restriction. Moreover, RIA evaluation of plasma IGFBP-2 is able to better reflect group differences than WLB.

Candidate gene markers associated with somatotropic axis and milk selection

One of the obstacles to progress in dairy cattle selection is that milk production traits are only expressed after the first calving. However, the use of the quantitative trait loci (QTL) technology will improve the efficiency of dairy industry with a positive image for the consumers. QTL are part of the genome showing a preponderant action and explaining the major part of variation of the trait production. At the present time, the two major strategies developed to detect such QTL are the candidate gene approach and the positional genetics approach. The somatotropic axis contains the most promising candidates in this respect, as it strongly regulates milk production. Then, the identification of favorable QTL associated with the somatotropic axis that are significantly correlated with genetic merits for milk production could lead to more effective selection programs.